+The Linux Kernel is provided under:
- NOTE! This copyright does *not* cover user programs that use kernel
- services by normal system calls - this is merely considered normal use
- of the kernel, and does *not* fall under the heading of "derived work".
- Also note that the GPL below is copyrighted by the Free Software
- Foundation, but the instance of code that it refers to (the Linux
- kernel) is copyrighted by me and others who actually wrote it.
+ SPDX-License-Identifier: GPL-2.0 WITH Linux-syscall-note
- Also note that the only valid version of the GPL as far as the kernel
- is concerned is _this_ particular version of the license (ie v2, not
- v2.2 or v3.x or whatever), unless explicitly otherwise stated.
+Being under the terms of the GNU General Public License version 2 only,
+according with:
- Linus Torvalds
+ LICENSES/preferred/GPL-2.0
-----------------------------------------
+With an explicit syscall exception, as stated at:
- GNU GENERAL PUBLIC LICENSE
- Version 2, June 1991
+ LICENSES/exceptions/Linux-syscall-note
- Copyright (C) 1989, 1991 Free Software Foundation, Inc.
- 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA
- Everyone is permitted to copy and distribute verbatim copies
- of this license document, but changing it is not allowed.
+In addition, other licenses may also apply. Please see:
- Preamble
+ Documentation/process/license-rules.rst
- The licenses for most software are designed to take away your
-freedom to share and change it. By contrast, the GNU General Public
-License is intended to guarantee your freedom to share and change free
-software--to make sure the software is free for all its users. This
-General Public License applies to most of the Free Software
-Foundation's software and to any other program whose authors commit to
-using it. (Some other Free Software Foundation software is covered by
-the GNU Library General Public License instead.) You can apply it to
-your programs, too.
-
- When we speak of free software, we are referring to freedom, not
-price. Our General Public Licenses are designed to make sure that you
-have the freedom to distribute copies of free software (and charge for
-this service if you wish), that you receive source code or can get it
-if you want it, that you can change the software or use pieces of it
-in new free programs; and that you know you can do these things.
-
- To protect your rights, we need to make restrictions that forbid
-anyone to deny you these rights or to ask you to surrender the rights.
-These restrictions translate to certain responsibilities for you if you
-distribute copies of the software, or if you modify it.
-
- For example, if you distribute copies of such a program, whether
-gratis or for a fee, you must give the recipients all the rights that
-you have. You must make sure that they, too, receive or can get the
-source code. And you must show them these terms so they know their
-rights.
-
- We protect your rights with two steps: (1) copyright the software, and
-(2) offer you this license which gives you legal permission to copy,
-distribute and/or modify the software.
-
- Also, for each author's protection and ours, we want to make certain
-that everyone understands that there is no warranty for this free
-software. If the software is modified by someone else and passed on, we
-want its recipients to know that what they have is not the original, so
-that any problems introduced by others will not reflect on the original
-authors' reputations.
-
- Finally, any free program is threatened constantly by software
-patents. We wish to avoid the danger that redistributors of a free
-program will individually obtain patent licenses, in effect making the
-program proprietary. To prevent this, we have made it clear that any
-patent must be licensed for everyone's free use or not licensed at all.
-
- The precise terms and conditions for copying, distribution and
-modification follow.
-\f
- GNU GENERAL PUBLIC LICENSE
- TERMS AND CONDITIONS FOR COPYING, DISTRIBUTION AND MODIFICATION
-
- 0. This License applies to any program or other work which contains
-a notice placed by the copyright holder saying it may be distributed
-under the terms of this General Public License. The "Program", below,
-refers to any such program or work, and a "work based on the Program"
-means either the Program or any derivative work under copyright law:
-that is to say, a work containing the Program or a portion of it,
-either verbatim or with modifications and/or translated into another
-language. (Hereinafter, translation is included without limitation in
-the term "modification".) Each licensee is addressed as "you".
-
-Activities other than copying, distribution and modification are not
-covered by this License; they are outside its scope. The act of
-running the Program is not restricted, and the output from the Program
-is covered only if its contents constitute a work based on the
-Program (independent of having been made by running the Program).
-Whether that is true depends on what the Program does.
-
- 1. You may copy and distribute verbatim copies of the Program's
-source code as you receive it, in any medium, provided that you
-conspicuously and appropriately publish on each copy an appropriate
-copyright notice and disclaimer of warranty; keep intact all the
-notices that refer to this License and to the absence of any warranty;
-and give any other recipients of the Program a copy of this License
-along with the Program.
-
-You may charge a fee for the physical act of transferring a copy, and
-you may at your option offer warranty protection in exchange for a fee.
-
- 2. You may modify your copy or copies of the Program or any portion
-of it, thus forming a work based on the Program, and copy and
-distribute such modifications or work under the terms of Section 1
-above, provided that you also meet all of these conditions:
-
- a) You must cause the modified files to carry prominent notices
- stating that you changed the files and the date of any change.
-
- b) You must cause any work that you distribute or publish, that in
- whole or in part contains or is derived from the Program or any
- part thereof, to be licensed as a whole at no charge to all third
- parties under the terms of this License.
-
- c) If the modified program normally reads commands interactively
- when run, you must cause it, when started running for such
- interactive use in the most ordinary way, to print or display an
- announcement including an appropriate copyright notice and a
- notice that there is no warranty (or else, saying that you provide
- a warranty) and that users may redistribute the program under
- these conditions, and telling the user how to view a copy of this
- License. (Exception: if the Program itself is interactive but
- does not normally print such an announcement, your work based on
- the Program is not required to print an announcement.)
-\f
-These requirements apply to the modified work as a whole. If
-identifiable sections of that work are not derived from the Program,
-and can be reasonably considered independent and separate works in
-themselves, then this License, and its terms, do not apply to those
-sections when you distribute them as separate works. But when you
-distribute the same sections as part of a whole which is a work based
-on the Program, the distribution of the whole must be on the terms of
-this License, whose permissions for other licensees extend to the
-entire whole, and thus to each and every part regardless of who wrote it.
-
-Thus, it is not the intent of this section to claim rights or contest
-your rights to work written entirely by you; rather, the intent is to
-exercise the right to control the distribution of derivative or
-collective works based on the Program.
-
-In addition, mere aggregation of another work not based on the Program
-with the Program (or with a work based on the Program) on a volume of
-a storage or distribution medium does not bring the other work under
-the scope of this License.
-
- 3. You may copy and distribute the Program (or a work based on it,
-under Section 2) in object code or executable form under the terms of
-Sections 1 and 2 above provided that you also do one of the following:
-
- a) Accompany it with the complete corresponding machine-readable
- source code, which must be distributed under the terms of Sections
- 1 and 2 above on a medium customarily used for software interchange; or,
-
- b) Accompany it with a written offer, valid for at least three
- years, to give any third party, for a charge no more than your
- cost of physically performing source distribution, a complete
- machine-readable copy of the corresponding source code, to be
- distributed under the terms of Sections 1 and 2 above on a medium
- customarily used for software interchange; or,
-
- c) Accompany it with the information you received as to the offer
- to distribute corresponding source code. (This alternative is
- allowed only for noncommercial distribution and only if you
- received the program in object code or executable form with such
- an offer, in accord with Subsection b above.)
-
-The source code for a work means the preferred form of the work for
-making modifications to it. For an executable work, complete source
-code means all the source code for all modules it contains, plus any
-associated interface definition files, plus the scripts used to
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-anything that is normally distributed (in either source or binary
-form) with the major components (compiler, kernel, and so on) of the
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-itself accompanies the executable.
-
-If distribution of executable or object code is made by offering
-access to copy from a designated place, then offering equivalent
-access to copy the source code from the same place counts as
-distribution of the source code, even though third parties are not
-compelled to copy the source along with the object code.
-\f
- 4. You may not copy, modify, sublicense, or distribute the Program
-except as expressly provided under this License. Any attempt
-otherwise to copy, modify, sublicense or distribute the Program is
-void, and will automatically terminate your rights under this License.
-However, parties who have received copies, or rights, from you under
-this License will not have their licenses terminated so long as such
-parties remain in full compliance.
-
- 5. You are not required to accept this License, since you have not
-signed it. However, nothing else grants you permission to modify or
-distribute the Program or its derivative works. These actions are
-prohibited by law if you do not accept this License. Therefore, by
-modifying or distributing the Program (or any work based on the
-Program), you indicate your acceptance of this License to do so, and
-all its terms and conditions for copying, distributing or modifying
-the Program or works based on it.
-
- 6. Each time you redistribute the Program (or any work based on the
-Program), the recipient automatically receives a license from the
-original licensor to copy, distribute or modify the Program subject to
-these terms and conditions. You may not impose any further
-restrictions on the recipients' exercise of the rights granted herein.
-You are not responsible for enforcing compliance by third parties to
-this License.
-
- 7. If, as a consequence of a court judgment or allegation of patent
-infringement or for any other reason (not limited to patent issues),
-conditions are imposed on you (whether by court order, agreement or
-otherwise) that contradict the conditions of this License, they do not
-excuse you from the conditions of this License. If you cannot
-distribute so as to satisfy simultaneously your obligations under this
-License and any other pertinent obligations, then as a consequence you
-may not distribute the Program at all. For example, if a patent
-license would not permit royalty-free redistribution of the Program by
-all those who receive copies directly or indirectly through you, then
-the only way you could satisfy both it and this License would be to
-refrain entirely from distribution of the Program.
-
-If any portion of this section is held invalid or unenforceable under
-any particular circumstance, the balance of the section is intended to
-apply and the section as a whole is intended to apply in other
-circumstances.
-
-It is not the purpose of this section to induce you to infringe any
-patents or other property right claims or to contest validity of any
-such claims; this section has the sole purpose of protecting the
-integrity of the free software distribution system, which is
-implemented by public license practices. Many people have made
-generous contributions to the wide range of software distributed
-through that system in reliance on consistent application of that
-system; it is up to the author/donor to decide if he or she is willing
-to distribute software through any other system and a licensee cannot
-impose that choice.
-
-This section is intended to make thoroughly clear what is believed to
-be a consequence of the rest of this License.
-\f
- 8. If the distribution and/or use of the Program is restricted in
-certain countries either by patents or by copyrighted interfaces, the
-original copyright holder who places the Program under this License
-may add an explicit geographical distribution limitation excluding
-those countries, so that distribution is permitted only in or among
-countries not thus excluded. In such case, this License incorporates
-the limitation as if written in the body of this License.
-
- 9. The Free Software Foundation may publish revised and/or new versions
-of the General Public License from time to time. Such new versions will
-be similar in spirit to the present version, but may differ in detail to
-address new problems or concerns.
-
-Each version is given a distinguishing version number. If the Program
-specifies a version number of this License which applies to it and "any
-later version", you have the option of following the terms and conditions
-either of that version or of any later version published by the Free
-Software Foundation. If the Program does not specify a version number of
-this License, you may choose any version ever published by the Free Software
-Foundation.
-
- 10. If you wish to incorporate parts of the Program into other free
-programs whose distribution conditions are different, write to the author
-to ask for permission. For software which is copyrighted by the Free
-Software Foundation, write to the Free Software Foundation; we sometimes
-make exceptions for this. Our decision will be guided by the two goals
-of preserving the free status of all derivatives of our free software and
-of promoting the sharing and reuse of software generally.
-
- NO WARRANTY
-
- 11. BECAUSE THE PROGRAM IS LICENSED FREE OF CHARGE, THERE IS NO WARRANTY
-FOR THE PROGRAM, TO THE EXTENT PERMITTED BY APPLICABLE LAW. EXCEPT WHEN
-OTHERWISE STATED IN WRITING THE COPYRIGHT HOLDERS AND/OR OTHER PARTIES
-PROVIDE THE PROGRAM "AS IS" WITHOUT WARRANTY OF ANY KIND, EITHER EXPRESSED
-OR IMPLIED, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES OF
-MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE. THE ENTIRE RISK AS
-TO THE QUALITY AND PERFORMANCE OF THE PROGRAM IS WITH YOU. SHOULD THE
-PROGRAM PROVE DEFECTIVE, YOU ASSUME THE COST OF ALL NECESSARY SERVICING,
-REPAIR OR CORRECTION.
-
- 12. IN NO EVENT UNLESS REQUIRED BY APPLICABLE LAW OR AGREED TO IN WRITING
-WILL ANY COPYRIGHT HOLDER, OR ANY OTHER PARTY WHO MAY MODIFY AND/OR
-REDISTRIBUTE THE PROGRAM AS PERMITTED ABOVE, BE LIABLE TO YOU FOR DAMAGES,
-INCLUDING ANY GENERAL, SPECIAL, INCIDENTAL OR CONSEQUENTIAL DAMAGES ARISING
-OUT OF THE USE OR INABILITY TO USE THE PROGRAM (INCLUDING BUT NOT LIMITED
-TO LOSS OF DATA OR DATA BEING RENDERED INACCURATE OR LOSSES SUSTAINED BY
-YOU OR THIRD PARTIES OR A FAILURE OF THE PROGRAM TO OPERATE WITH ANY OTHER
-PROGRAMS), EVEN IF SUCH HOLDER OR OTHER PARTY HAS BEEN ADVISED OF THE
-POSSIBILITY OF SUCH DAMAGES.
-
- END OF TERMS AND CONDITIONS
-\f
- How to Apply These Terms to Your New Programs
-
- If you develop a new program, and you want it to be of the greatest
-possible use to the public, the best way to achieve this is to make it
-free software which everyone can redistribute and change under these terms.
-
- To do so, attach the following notices to the program. It is safest
-to attach them to the start of each source file to most effectively
-convey the exclusion of warranty; and each file should have at least
-the "copyright" line and a pointer to where the full notice is found.
-
- <one line to give the program's name and a brief idea of what it does.>
- Copyright (C) <year> <name of author>
-
- This program is free software; you can redistribute it and/or modify
- it under the terms of the GNU General Public License as published by
- the Free Software Foundation; either version 2 of the License, or
- (at your option) any later version.
-
- This program is distributed in the hope that it will be useful,
- but WITHOUT ANY WARRANTY; without even the implied warranty of
- MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
- GNU General Public License for more details.
-
- You should have received a copy of the GNU General Public License
- along with this program; if not, write to the Free Software
- Foundation, Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA
-
-
-Also add information on how to contact you by electronic and paper mail.
-
-If the program is interactive, make it output a short notice like this
-when it starts in an interactive mode:
-
- Gnomovision version 69, Copyright (C) year name of author
- Gnomovision comes with ABSOLUTELY NO WARRANTY; for details type `show w'.
- This is free software, and you are welcome to redistribute it
- under certain conditions; type `show c' for details.
-
-The hypothetical commands `show w' and `show c' should show the appropriate
-parts of the General Public License. Of course, the commands you use may
-be called something other than `show w' and `show c'; they could even be
-mouse-clicks or menu items--whatever suits your program.
-
-You should also get your employer (if you work as a programmer) or your
-school, if any, to sign a "copyright disclaimer" for the program, if
-necessary. Here is a sample; alter the names:
-
- Yoyodyne, Inc., hereby disclaims all copyright interest in the program
- `Gnomovision' (which makes passes at compilers) written by James Hacker.
-
- <signature of Ty Coon>, 1 April 1989
- Ty Coon, President of Vice
-
-This General Public License does not permit incorporating your program into
-proprietary programs. If your program is a subroutine library, you may
-consider it more useful to permit linking proprietary applications with the
-library. If this is what you want to do, use the GNU Library General
-Public License instead of this License.
+for more details.
--- /dev/null
+sysfs interface common for all infiniband devices
+-------------------------------------------------
+
+What: /sys/class/infiniband/<device>/node_type
+What: /sys/class/infiniband/<device>/node_guid
+What: /sys/class/infiniband/<device>/sys_image_guid
+Date: Apr, 2005
+KernelVersion: v2.6.12
+Contact: linux-rdma@vger.kernel.org
+Description:
+ node_type: (RO) Node type (CA, RNIC, usNIC, usNIC UDP,
+ switch or router)
+
+ node_guid: (RO) Node GUID
+
+ sys_image_guid: (RO) System image GUID
+
+
+What: /sys/class/infiniband/<device>/node_desc
+Date: Feb, 2006
+KernelVersion: v2.6.17
+Contact: linux-rdma@vger.kernel.org
+Description:
+ (RW) Update the node description with information such as the
+ node's hostname, so that IB network management software can tie
+ its view to the real world.
+
+
+What: /sys/class/infiniband/<device>/fw_ver
+Date: Jun, 2016
+KernelVersion: v4.10
+Contact: linux-rdma@vger.kernel.org
+Description:
+ (RO) Display firmware version
+
+
+What: /sys/class/infiniband/<device>/ports/<port-num>/lid
+What: /sys/class/infiniband/<device>/ports/<port-num>/rate
+What: /sys/class/infiniband/<device>/ports/<port-num>/lid_mask_count
+What: /sys/class/infiniband/<device>/ports/<port-num>/sm_sl
+What: /sys/class/infiniband/<device>/ports/<port-num>/sm_lid
+What: /sys/class/infiniband/<device>/ports/<port-num>/state
+What: /sys/class/infiniband/<device>/ports/<port-num>/phys_state
+What: /sys/class/infiniband/<device>/ports/<port-num>/cap_mask
+Date: Apr, 2005
+KernelVersion: v2.6.12
+Contact: linux-rdma@vger.kernel.org
+Description:
+
+ lid: (RO) Port LID
+
+ rate: (RO) Port data rate (active width * active
+ speed)
+
+ lid_mask_count: (RO) Port LID mask count
+
+ sm_sl: (RO) Subnet manager SL for port's subnet
+
+ sm_lid: (RO) Subnet manager LID for port's subnet
+
+ state: (RO) Port state (DOWN, INIT, ARMED, ACTIVE or
+ ACTIVE_DEFER)
+
+ phys_state: (RO) Port physical state (Sleep, Polling,
+ LinkUp, etc)
+
+ cap_mask: (RO) Port capability mask. 2 bits here are
+ settable- IsCommunicationManagementSupported
+ (set when CM module is loaded) and IsSM (set via
+ open of issmN file).
+
+
+What: /sys/class/infiniband/<device>/ports/<port-num>/link_layer
+Date: Oct, 2010
+KernelVersion: v2.6.37
+Contact: linux-rdma@vger.kernel.org
+Description:
+ (RO) Link layer type information (Infiniband or Ethernet type)
+
+
+What: /sys/class/infiniband/<device>/ports/<port-num>/counters/symbol_error
+What: /sys/class/infiniband/<device>/ports/<port-num>/counters/port_rcv_errors
+What: /sys/class/infiniband/<device>/ports/<port-num>/counters/port_rcv_remote_physical_errors
+What: /sys/class/infiniband/<device>/ports/<port-num>/counters/port_rcv_switch_relay_errors
+What: /sys/class/infiniband/<device>/ports/<port-num>/counters/link_error_recovery
+What: /sys/class/infiniband/<device>/ports/<port-num>/counters/port_xmit_constraint_errors
+What: /sys/class/infiniband/<device>/ports/<port-num>/counters/port_rcv_contraint_errors
+What: /sys/class/infiniband/<device>/ports/<port-num>/counters/local_link_integrity_errors
+What: /sys/class/infiniband/<device>/ports/<port-num>/counters/excessive_buffer_overrun_errors
+What: /sys/class/infiniband/<device>/ports/<port-num>/counters/port_xmit_data
+What: /sys/class/infiniband/<device>/ports/<port-num>/counters/port_rcv_data
+What: /sys/class/infiniband/<device>/ports/<port-num>/counters/port_xmit_packets
+What: /sys/class/infiniband/<device>/ports/<port-num>/counters/port_rcv_packets
+What: /sys/class/infiniband/<device>/ports/<port-num>/counters/unicast_rcv_packets
+What: /sys/class/infiniband/<device>/ports/<port-num>/counters/unicast_xmit_packets
+What: /sys/class/infiniband/<device>/ports/<port-num>/counters/multicast_rcv_packets
+What: /sys/class/infiniband/<device>/ports/<port-num>/counters/multicast_xmit_packets
+What: /sys/class/infiniband/<device>/ports/<port-num>/counters/link_downed
+What: /sys/class/infiniband/<device>/ports/<port-num>/counters/port_xmit_discards
+What: /sys/class/infiniband/<device>/ports/<port-num>/counters/VL15_dropped
+What: /sys/class/infiniband/<device>/ports/<port-num>/counters/port_xmit_wait
+Date: Apr, 2005
+KernelVersion: v2.6.12
+Contact: linux-rdma@vger.kernel.org
+Description:
+ Errors info:
+ -----------
+
+ symbol_error: (RO) Total number of minor link errors detected on
+ one or more physical lanes.
+
+ port_rcv_errors : (RO) Total number of packets containing an
+ error that were received on the port.
+
+ port_rcv_remote_physical_errors : (RO) Total number of packets
+ marked with the EBP delimiter received on the port.
+
+ port_rcv_switch_relay_errors : (RO) Total number of packets
+ received on the port that were discarded because they could not
+ be forwarded by the switch relay.
+
+ link_error_recovery: (RO) Total number of times the Port
+ Training state machine has successfully completed the link error
+ recovery process.
+
+ port_xmit_constraint_errors: (RO) Total number of packets not
+ transmitted from the switch physical port due to outbound raw
+ filtering or failing outbound partition or IP version check.
+
+ port_rcv_constraint_errors: (RO) Total number of packets
+ received on the switch physical port that are discarded due to
+ inbound raw filtering or failing inbound partition or IP version
+ check.
+
+ local_link_integrity_errors: (RO) The number of times that the
+ count of local physical errors exceeded the threshold specified
+ by LocalPhyErrors
+
+ excessive_buffer_overrun_errors: (RO) This counter, indicates an
+ input buffer overrun. It indicates possible misconfiguration of
+ a port, either by the Subnet Manager (SM) or by user
+ intervention. It can also indicate hardware issues or extremely
+ poor link signal integrity
+
+ Data info:
+ ---------
+
+ port_xmit_data: (RO) Total number of data octets, divided by 4
+ (lanes), transmitted on all VLs. This is 64 bit counter
+
+ port_rcv_data: (RO) Total number of data octets, divided by 4
+ (lanes), received on all VLs. This is 64 bit counter.
+
+ port_xmit_packets: (RO) Total number of packets transmitted on
+ all VLs from this port. This may include packets with errors.
+ This is 64 bit counter.
+
+ port_rcv_packets: (RO) Total number of packets (this may include
+ packets containing Errors. This is 64 bit counter.
+
+ link_downed: (RO) Total number of times the Port Training state
+ machine has failed the link error recovery process and downed
+ the link.
+
+ unicast_rcv_packets: (RO) Total number of unicast packets,
+ including unicast packets containing errors.
+
+ unicast_xmit_packets: (RO) Total number of unicast packets
+ transmitted on all VLs from the port. This may include unicast
+ packets with errors.
+
+ multicast_rcv_packets: (RO) Total number of multicast packets,
+ including multicast packets containing errors.
+
+ multicast_xmit_packets: (RO) Total number of multicast packets
+ transmitted on all VLs from the port. This may include multicast
+ packets with errors.
+
+ Misc info:
+ ---------
+
+ port_xmit_discards: (RO) Total number of outbound packets
+ discarded by the port because the port is down or congested.
+
+ VL15_dropped: (RO) Number of incoming VL15 packets dropped due
+ to resource limitations (e.g., lack of buffers) of the port.
+
+ port_xmit_wait: (RO) The number of ticks during which the port
+ had data to transmit but no data was sent during the entire tick
+ (either because of insufficient credits or because of lack of
+ arbitration).
+
+ Each of these files contains the corresponding value from the
+ port's Performance Management PortCounters attribute, as
+ described in the InfiniBand Architecture Specification.
+
+
+What: /sys/class/infiniband/<device-name>/hw_counters/lifespan
+What: /sys/class/infiniband/<device-name>/ports/<port-num>/hw_counters/lifespan
+Date: May, 2016
+KernelVersion: 4.6
+Contact: linux-rdma@vger.kernel.org
+Description:
+ The optional "hw_counters" subdirectory can be under either the
+ parent device or the port subdirectories or both. If present,
+ there are a list of counters provided by the hardware. They may
+ match some of the counters in the counters directory, but they
+ often include many other counters. In addition to the various
+ counters, there will be a file named "lifespan" that configures
+ how frequently the core should update the counters when they are
+ being accessed (counters are not updated if they are not being
+ accessed). The lifespan is in milliseconds and defaults to 10
+ unless set to something else by the driver. Users may echo a
+ value between 0-10000 to the lifespan file to set the length
+ of time between updates in milliseconds.
+
+
+What: /sys/class/infiniband/<hca>/ports/<port-number>/gid_attrs/ndevs/<gid-index>
+Date: November 29, 2015
+KernelVersion: 4.4.0
+Contact: linux-rdma@vger.kernel.org
+Description: The net-device's name associated with the GID resides
+ at index <gid-index>.
+
+What: /sys/class/infiniband/<hca>/ports/<port-number>/gid_attrs/types/<gid-index>
+Date: November 29, 2015
+KernelVersion: 4.4.0
+Contact: linux-rdma@vger.kernel.org
+Description: The RoCE type of the associated GID resides at index <gid-index>.
+ This could either be "IB/RoCE v1" for IB and RoCE v1 based GIDs
+ or "RoCE v2" for RoCE v2 based GIDs.
+
+
+What: /sys/class/infiniband_mad/umadN/ibdev
+What: /sys/class/infiniband_mad/umadN/port
+What: /sys/class/infiniband_mad/issmN/ibdev
+What: /sys/class/infiniband_mad/issmN/port
+Date: Apr, 2005
+KernelVersion: v2.6.12
+Contact: linux-rdma@vger.kernel.org
+Description:
+ Each port of each InfiniBand device has a "umad" device and an
+ "issm" device attached. For example, a two-port HCA will have
+ two umad devices and two issm devices, while a switch will have
+ one device of each type (for switch port 0).
+
+ ibdev: (RO) Show Infiniband (IB) device name
+
+ port: (RO) Display port number
+
+
+What: /sys/class/infiniband_mad/abi_version
+Date: Apr, 2005
+KernelVersion: v2.6.12
+Contact: linux-rdma@vger.kernel.org
+Description:
+ (RO) Value is incremented if any changes are made that break
+ userspace ABI compatibility of umad & issm devices.
+
+
+What: /sys/class/infiniband_cm/ucmN/ibdev
+Date: Oct, 2005
+KernelVersion: v2.6.14
+Contact: linux-rdma@vger.kernel.org
+Description:
+ (RO) Display Infiniband (IB) device name
+
+
+What: /sys/class/infiniband_cm/abi_version
+Date: Oct, 2005
+KernelVersion: v2.6.14
+Contact: linux-rdma@vger.kernel.org
+Description:
+ (RO) Value is incremented if any changes are made that break
+ userspace ABI compatibility of ucm devices.
+
+
+What: /sys/class/infiniband_verbs/uverbsN/ibdev
+What: /sys/class/infiniband_verbs/uverbsN/abi_version
+Date: Sept, 2005
+KernelVersion: v2.6.14
+Contact: linux-rdma@vger.kernel.org
+Description:
+ ibdev: (RO) Display Infiniband (IB) device name
+
+ abi_version: (RO) Show ABI version of IB device specific
+ interfaces.
+
+
+What: /sys/class/infiniband_verbs/abi_version
+Date: Sep, 2005
+KernelVersion: v2.6.14
+Contact: linux-rdma@vger.kernel.org
+Description:
+ (RO) Value is incremented if any changes are made that break
+ userspace ABI compatibility of uverbs devices.
+
+
+sysfs interface for Mellanox IB HCA low-level driver (mthca)
+------------------------------------------------------------
+
+What: /sys/class/infiniband/mthcaX/hw_rev
+What: /sys/class/infiniband/mthcaX/hca_type
+What: /sys/class/infiniband/mthcaX/board_id
+Date: Apr, 2005
+KernelVersion: v2.6.12
+Contact: linux-rdma@vger.kernel.org
+Description:
+ hw_rev: (RO) Hardware revision number
+
+ hca_type: (RO) Host Channel Adapter type: MT23108, MT25208
+ (MT23108 compat mode), MT25208 or MT25204
+
+ board_id: (RO) Manufacturing board ID
+
+
+sysfs interface for Chelsio T3 RDMA Driver (cxgb3)
+--------------------------------------------------
+
+What: /sys/class/infiniband/cxgb3_X/hw_rev
+What: /sys/class/infiniband/cxgb3_X/hca_type
+What: /sys/class/infiniband/cxgb3_X/board_id
+Date: Feb, 2007
+KernelVersion: v2.6.21
+Contact: linux-rdma@vger.kernel.org
+Description:
+ hw_rev: (RO) Hardware revision number
+
+ hca_type: (RO) HCA type. Here it is a driver short name.
+ It should normally match the name in its bus
+ driver structure (e.g. pci_driver::name).
+
+ board_id: (RO) Manufacturing board id
+
+
+sysfs interface for Mellanox ConnectX HCA IB driver (mlx4)
+----------------------------------------------------------
+
+What: /sys/class/infiniband/mlx4_X/hw_rev
+What: /sys/class/infiniband/mlx4_X/hca_type
+What: /sys/class/infiniband/mlx4_X/board_id
+Date: Sep, 2007
+KernelVersion: v2.6.24
+Contact: linux-rdma@vger.kernel.org
+Description:
+ hw_rev: (RO) Hardware revision number
+
+ hca_type: (RO) Host channel adapter type
+
+ board_id: (RO) Manufacturing board ID
+
+
+What: /sys/class/infiniband/mlx4_X/iov/ports/<port-num>/gids/<n>
+What: /sys/class/infiniband/mlx4_X/iov/ports/<port-num>/admin_guids/<n>
+What: /sys/class/infiniband/mlx4_X/iov/ports/<port-num>/pkeys/<n>
+What: /sys/class/infiniband/mlx4_X/iov/ports/<port-num>/mcgs/
+What: /sys/class/infiniband/mlx4_X/iov/ports/<pci-slot-num>/ports/<m>/gid_idx/0
+What: /sys/class/infiniband/mlx4_X/iov/ports/<pci-slot-num>/ports/<m>/pkey_idx/<n>
+Date: Aug, 2012
+KernelVersion: v3.6.15
+Contact: linux-rdma@vger.kernel.org
+Description:
+ The sysfs iov directory is used to manage and examine the port
+ P_Key and guid paravirtualization. This directory is added only
+ for the master -- slaves do not have it.
+
+ Under iov/ports, the administrator may examine the gid and P_Key
+ tables as they are present in the device (and as are seen in the
+ "network view" presented to the SM).
+
+ The "pkeys" and "gids" subdirectories contain one file for each
+ entry in the port's P_Key or GID table respectively. For
+ example, ports/1/pkeys/10 contains the value at index 10 in port
+ 1's P_Key table.
+
+ gids/<n>: (RO) The physical port gids n = 0..127
+
+ admin_guids/<n>: (RW) Allows examining or changing the
+ administrative state of a given GUID
+ n = 0..127
+
+ pkeys/<n>: (RO) Displays the contents of the physical
+ key table n = 0..126
+
+ mcgs/: (RO) Muticast group table
+
+ <m>/gid_idx/0: (RO) Display the GID mapping m = 1..2
+
+ <m>/pkey_idx/<n>: (RW) Writable except for RoCE pkeys.
+ m = 1..2, n = 0..126
+
+ Under the iov/<pci slot number>
+ directories, the admin may map the index
+ numbers in the physical tables (as under
+ iov/ports) to the paravirtualized index
+ numbers that guests see.
+
+ For example, if the administrator, for
+ port 1 on guest 2 maps physical pkey
+ index 10 to virtual index 1, then that
+ guest, whenever it uses its pkey index
+ 1, will actually be using the real pkey
+ index 10.
+
+
+What: /sys/class/infiniband/mlx4_X/iov/<pci-slot-num>/ports/<m>/smi_enabled
+What: /sys/class/infiniband/mlx4_X/iov/<pci-slot-num>/ports/<m>/enable_smi_admin
+Date: May, 2014
+KernelVersion: v3.15.7
+Contact: linux-rdma@vger.kernel.org
+Description:
+ Enabling QP0 on VFs for selected VF/port. By default, no VFs are
+ enabled for QP0 operation.
+
+ smi_enabled: (RO) Indicates whether smi is currently enabled
+ for the indicated VF/port
+
+ enable_smi_admin:(RW) Used by the admin to request that smi
+ capability be enabled or disabled for the
+ indicated VF/port. 0 = disable, 1 = enable.
+
+ The requested enablement will occur at the next reset of the VF
+ (e.g. driver restart on the VM which owns the VF).
+
+
+sysfs interface for NetEffect RNIC Low-Level iWARP driver (nes)
+---------------------------------------------------------------
+
+What: /sys/class/infiniband/nesX/hw_rev
+What: /sys/class/infiniband/nesX/hca_type
+What: /sys/class/infiniband/nesX/board_id
+Date: Feb, 2008
+KernelVersion: v2.6.25
+Contact: linux-rdma@vger.kernel.org
+Description:
+ hw_rev: (RO) Hardware revision number
+
+ hca_type: (RO) Host Channel Adapter type (NEX020)
+
+ board_id: (RO) Manufacturing board id
+
+
+sysfs interface for Chelsio T4/T5 RDMA driver (cxgb4)
+-----------------------------------------------------
+
+What: /sys/class/infiniband/cxgb4_X/hw_rev
+What: /sys/class/infiniband/cxgb4_X/hca_type
+What: /sys/class/infiniband/cxgb4_X/board_id
+Date: Apr, 2010
+KernelVersion: v2.6.35
+Contact: linux-rdma@vger.kernel.org
+Description:
+
+ hw_rev: (RO) Hardware revision number
+
+ hca_type: (RO) Driver short name. Should normally match
+ the name in its bus driver structure (e.g.
+ pci_driver::name)
+
+ board_id: (RO) Manufacturing board id. (Vendor + device
+ information)
+
+
+sysfs interface for Intel IB driver qib
+---------------------------------------
+
+What: /sys/class/infiniband/qibX/version
+What: /sys/class/infiniband/qibX/hw_rev
+What: /sys/class/infiniband/qibX/hca_type
+What: /sys/class/infiniband/qibX/board_id
+What: /sys/class/infiniband/qibX/boardversion
+What: /sys/class/infiniband/qibX/nctxts
+What: /sys/class/infiniband/qibX/localbus_info
+What: /sys/class/infiniband/qibX/tempsense
+What: /sys/class/infiniband/qibX/serial
+What: /sys/class/infiniband/qibX/nfreectxts
+What: /sys/class/infiniband/qibX/chip_reset
+Date: May, 2010
+KernelVersion: v2.6.35
+Contact: linux-rdma@vger.kernel.org
+Description:
+ version: (RO) Display version information of installed software
+ and drivers.
+
+ hw_rev: (RO) Hardware revision number
+
+ hca_type: (RO) Host channel adapter type
+
+ board_id: (RO) Manufacturing board id
+
+ boardversion: (RO) Current version of the chip architecture
+
+ nctxts: (RO) Return the number of user ports (contexts)
+ available
+
+ localbus_info: (RO) Human readable localbus info
+
+ tempsense: (RO) Display temp sense registers in decimal
+
+ serial: (RO) Serial number of the HCA
+
+ nfreectxts: (RO) The number of free user ports (contexts)
+ available.
+
+ chip_reset: (WO) Reset the chip if possible by writing
+ "reset" to this file. Only allowed if no user
+ contexts are open that use chip resources.
+
+
+What: /sys/class/infiniband/qibX/ports/N/sl2vl/[0-15]
+Date: May, 2010
+KernelVersion: v2.6.35
+Contact: linux-rdma@vger.kernel.org
+Description:
+ (RO) The directory contains 16 files numbered 0-15 that specify
+ the Service Level (SL). Listing the SL files returns the Virtual
+ Lane (VL) as programmed by the SL.
+
+What: /sys/class/infiniband/qibX/ports/N/CCMgtA/cc_settings_bin
+What: /sys/class/infiniband/qibX/ports/N/CCMgtA/cc_table_bin
+Date: May, 2010
+KernelVersion: v2.6.35
+Contact: linux-rdma@vger.kernel.org
+Description:
+ Per-port congestion control. Both are binary attributes.
+
+ cc_table_bin: (RO) Congestion control table size followed by
+ table entries.
+
+ cc_settings_bin:(RO) Congestion settings: port control, control
+ map and an array of 16 entries for the
+ congestion entries - increase, timer, event log
+ trigger threshold and the minimum injection rate
+ delay.
+
+What: /sys/class/infiniband/qibX/ports/N/linkstate/loopback
+What: /sys/class/infiniband/qibX/ports/N/linkstate/led_override
+What: /sys/class/infiniband/qibX/ports/N/linkstate/hrtbt_enable
+What: /sys/class/infiniband/qibX/ports/N/linkstate/status
+What: /sys/class/infiniband/qibX/ports/N/linkstate/status_str
+Date: May, 2010
+KernelVersion: v2.6.35
+Contact: linux-rdma@vger.kernel.org
+Description:
+ [to be documented]
+
+ loopback: (WO)
+ led_override: (WO)
+ hrtbt_enable: (RW)
+ status: (RO)
+
+ status_str: (RO) Displays information about the link state,
+ possible cable/switch problems, and hardware
+ errors. Possible states are- "Initted",
+ "Present", "IB_link_up", "IB_configured" or
+ "Fatal_Hardware_Error".
+
+What: /sys/class/infiniband/qibX/ports/N/diag_counters/rc_resends
+What: /sys/class/infiniband/qibX/ports/N/diag_counters/seq_naks
+What: /sys/class/infiniband/qibX/ports/N/diag_counters/rdma_seq
+What: /sys/class/infiniband/qibX/ports/N/diag_counters/rnr_naks
+What: /sys/class/infiniband/qibX/ports/N/diag_counters/other_naks
+What: /sys/class/infiniband/qibX/ports/N/diag_counters/rc_timeouts
+What: /sys/class/infiniband/qibX/ports/N/diag_counters/look_pkts
+What: /sys/class/infiniband/qibX/ports/N/diag_counters/pkt_drops
+What: /sys/class/infiniband/qibX/ports/N/diag_counters/dma_wait
+What: /sys/class/infiniband/qibX/ports/N/diag_counters/unaligned
+Date: May, 2010
+KernelVersion: v2.6.35
+Contact: linux-rdma@vger.kernel.org
+Description:
+ [to be documented]
+
+
+sysfs interface for Mellanox Connect-IB HCA driver mlx5
+-------------------------------------------------------
+
+What: /sys/class/infiniband/mlx5_X/hw_rev
+What: /sys/class/infiniband/mlx5_X/hca_type
+What: /sys/class/infiniband/mlx5_X/reg_pages
+What: /sys/class/infiniband/mlx5_X/fw_pages
+Date: Jul, 2013
+KernelVersion: v3.11
+Contact: linux-rdma@vger.kernel.org
+Description:
+ [to be documented]
+
+
+sysfs interface for Cisco VIC (usNIC) Verbs Driver
+--------------------------------------------------
+
+What: /sys/class/infiniband/usnic_X/board_id
+What: /sys/class/infiniband/usnic_X/config
+What: /sys/class/infiniband/usnic_X/qp_per_vf
+What: /sys/class/infiniband/usnic_X/max_vf
+What: /sys/class/infiniband/usnic_X/cq_per_vf
+What: /sys/class/infiniband/usnic_X/iface
+Date: Sep, 2013
+KernelVersion: v3.14
+Contact: Christian Benvenuti <benve@cisco.com>,
+ Dave Goodell <dgoodell@cisco.com>,
+ linux-rdma@vger.kernel.org
+Description:
+
+ board_id: (RO) Manufacturing board id
+
+ config: (RO) Report the configuration for this PF
+
+ qp_per_vf: (RO) Queue pairs per virtual function.
+
+ max_vf: (RO) Max virtual functions
+
+ cq_per_vf: (RO) Completion queue per virtual function
+
+ iface: (RO) Shows which network interface this usNIC
+ entry is associated to (visible with ifconfig).
+
+What: /sys/class/infiniband/usnic_X/qpn/summary
+What: /sys/class/infiniband/usnic_X/qpn/context
+Date: Sep, 2013
+KernelVersion: v3.14
+Contact: Christian Benvenuti <benve@cisco.com>,
+ Dave Goodell <dgoodell@cisco.com>,
+ linux-rdma@vger.kernel.org
+Description:
+ [to be documented]
+
+
+sysfs interface for Emulex RoCE HCA Driver
+------------------------------------------
+
+What: /sys/class/infiniband/ocrdmaX/hw_rev
+Date: Feb, 2014
+KernelVersion: v3.14
+Description:
+ hw_rev: (RO) Hardware revision number
+
+What: /sys/class/infiniband/ocrdmaX/hca_type
+Date: Jun, 2014
+KernelVersion: v3.16
+Contact: linux-rdma@vger.kernel.org
+Description:
+ hca_type: (RO) Display FW version
+
+
+sysfs interface for Intel Omni-Path driver (HFI1)
+-------------------------------------------------
+
+What: /sys/class/infiniband/hfi1_X/hw_rev
+What: /sys/class/infiniband/hfi1_X/board_id
+What: /sys/class/infiniband/hfi1_X/nctxts
+What: /sys/class/infiniband/hfi1_X/serial
+What: /sys/class/infiniband/hfi1_X/chip_reset
+What: /sys/class/infiniband/hfi1_X/boardversion
+What: /sys/class/infiniband/hfi1_X/nfreectxts
+What: /sys/class/infiniband/hfi1_X/tempsense
+Date: May, 2016
+KernelVersion: v4.6
+Contact: linux-rdma@vger.kernel.org
+Description:
+ hw_rev: (RO) Hardware revision number
+
+ board_id: (RO) Manufacturing board id
+
+ nctxts: (RO) Total contexts available.
+
+ serial: (RO) Board serial number
+
+ chip_reset: (WO) Write "reset" to this file to reset the
+ chip if possible. Only allowed if no user
+ contexts are open that use chip resources.
+
+ boardversion: (RO) Human readable board info
+
+ nfreectxts: (RO) The number of free user ports (contexts)
+ available.
+
+ tempsense: (RO) Thermal sense information
+
+
+What: /sys/class/infiniband/hfi1_X/ports/N/CCMgtA/cc_settings_bin
+What: /sys/class/infiniband/hfi1_X/ports/N/CCMgtA/cc_table_bin
+What: /sys/class/infiniband/hfi1_X/ports/N/CCMgtA/cc_prescan
+Date: May, 2016
+KernelVersion: v4.6
+Contact: linux-rdma@vger.kernel.org
+Description:
+ Per-port congestion control.
+
+ cc_table_bin: (RO) CCA tables used by PSM2 Congestion control
+ table size followed by table entries. Binary
+ attribute.
+
+ cc_settings_bin:(RO) Congestion settings: port control, control
+ map and an array of 16 entries for the
+ congestion entries - increase, timer, event log
+ trigger threshold and the minimum injection rate
+ delay. Binary attribute.
+
+ cc_prescan: (RW) enable prescanning for faster BECN
+ response. Write "on" to enable and "off" to
+ disable.
+
+What: /sys/class/infiniband/hfi1_X/ports/N/sc2vl/[0-31]
+What: /sys/class/infiniband/hfi1_X/ports/N/sl2sc/[0-31]
+What: /sys/class/infiniband/hfi1_X/ports/N/vl2mtu/[0-15]
+Date: May, 2016
+KernelVersion: v4.6
+Contact: linux-rdma@vger.kernel.org
+Description:
+ sc2vl/: (RO) 32 files (0 - 31) used to translate sl->vl
+
+ sl2sc/: (RO) 32 files (0 - 31) used to translate sl->sc
+
+ vl2mtu/: (RO) 16 files (0 - 15) used to determine MTU for vl
+
+
+What: /sys/class/infiniband/hfi1_X/sdma_N/cpu_list
+What: /sys/class/infiniband/hfi1_X/sdma_N/vl
+Date: Sept, 2016
+KernelVersion: v4.8
+Contact: linux-rdma@vger.kernel.org
+Description:
+ sdma<N>/ contains one directory per sdma engine (0 - 15)
+
+ cpu_list: (RW) List of cpus for user-process to sdma
+ engine assignment.
+
+ vl: (RO) Displays the virtual lane (vl) the sdma
+ engine maps to.
+
+ This interface gives the user control on the affinity settings
+ for the device. As an example, to set an sdma engine irq
+ affinity and thread affinity of a user processes to use the
+ sdma engine, which is "near" in terms of NUMA configuration, or
+ physical cpu location, the user will do:
+
+ echo "3" > /proc/irq/<N>/smp_affinity_list
+ echo "4-7" > /sys/devices/.../sdma3/cpu_list
+ cat /sys/devices/.../sdma3/vl
+ 0
+ echo "8" > /proc/irq/<M>/smp_affinity_list
+ echo "9-12" > /sys/devices/.../sdma4/cpu_list
+ cat /sys/devices/.../sdma4/vl
+ 1
+
+ to make sure that when a process runs on cpus 4,5,6, or 7, and
+ uses vl=0, then sdma engine 3 is selected by the driver, and
+ also the interrupt of the sdma engine 3 is steered to cpu 3.
+ Similarly, when a process runs on cpus 9,10,11, or 12 and sets
+ vl=1, then engine 4 will be selected and the irq of the sdma
+ engine 4 is steered to cpu 8. This assumes that in the above N
+ is the irq number of "sdma3", and M is irq number of "sdma4" in
+ the /proc/interrupts file.
+
+
+sysfs interface for Intel(R) X722 iWARP i40iw driver
+----------------------------------------------------
+
+What: /sys/class/infiniband/i40iwX/hw_rev
+What: /sys/class/infiniband/i40iwX/hca_type
+What: /sys/class/infiniband/i40iwX/board_id
+Date: Jan, 2016
+KernelVersion: v4.10
+Contact: linux-rdma@vger.kernel.org
+Description:
+ hw_rev: (RO) Hardware revision number
+
+ hca_type: (RO) Show HCA type (I40IW)
+
+ board_id: (RO) I40IW board ID
+
+
+sysfs interface for QLogic qedr NIC Driver
+------------------------------------------
+
+What: /sys/class/infiniband/qedrX/hw_rev
+What: /sys/class/infiniband/qedrX/hca_type
+Date: Oct, 2016
+KernelVersion: v4.10
+Contact: linux-rdma@vger.kernel.org
+Description:
+
+ hw_rev: (RO) Hardware revision number
+
+ hca_type: (RO) Display HCA type
+
+
+sysfs interface for VMware Paravirtual RDMA driver
+--------------------------------------------------
+
+What: /sys/class/infiniband/vmw_pvrdmaX/hw_rev
+What: /sys/class/infiniband/vmw_pvrdmaX/hca_type
+What: /sys/class/infiniband/vmw_pvrdmaX/board_id
+Date: Oct, 2016
+KernelVersion: v4.10
+Contact: linux-rdma@vger.kernel.org
+Description:
+
+ hw_rev: (RO) Hardware revision number
+
+ hca_type: (RO) Host channel adapter type
+
+ board_id: (RO) Display PVRDMA manufacturing board ID
+
+
+sysfs interface for Broadcom NetXtreme-E RoCE driver
+----------------------------------------------------
+
+What: /sys/class/infiniband/bnxt_reX/hw_rev
+What: /sys/class/infiniband/bnxt_reX/hca_type
+Date: Feb, 2017
+KernelVersion: v4.11
+Contact: linux-rdma@vger.kernel.org
+Description:
+ hw_rev: (RO) Hardware revision number
+
+ hca_type: (RO) Host channel adapter type
--- /dev/null
+What: /sys/block/etherd*/mac
+Date: Apr, 2005
+KernelVersion: v2.6.12
+Contact: Ed L. Cashin <ed.cashin@acm.org>
+Description:
+ (RO) The ethernet address of the remote Ata over Ethernet (AoE)
+ device.
+
+What: /sys/block/etherd*/netif
+Date: Apr, 2005
+KernelVersion: v2.6.12
+Contact: Ed L. Cashin <ed.cashin@acm.org>
+Description:
+ (RO) The names of the network interfaces on the localhost (comma
+ separated) through which we are communicating with the remote
+ AoE device.
+
+What: /sys/block/etherd*/state
+Date: Apr, 2005
+KernelVersion: v2.6.12
+Contact: Ed L. Cashin <ed.cashin@acm.org>
+Description:
+ (RO) Device status. The state attribute is "up" when the device
+ is ready for I/O and "down" if detected but unusable. The
+ "down,closewait" state shows that the device is still open and
+ cannot come up again until it has been closed. The "up,kickme"
+ state means that the driver wants to send more commands to the
+ target but found out there were already the max number of
+ commands waiting for a response. It will retry again after being
+ kicked by the periodic timer handler routine.
+
+What: /sys/block/etherd*/firmware-version
+Date: Apr, 2005
+KernelVersion: v2.6.12
+Contact: Ed L. Cashin <ed.cashin@acm.org>
+Description:
+ (RO) Version of the firmware in the target.
+
+What: /sys/block/etherd*/payload
+Date: Dec, 2012
+KernelVersion: v3.10
+Contact: Ed L. Cashin <ed.cashin@acm.org>
+Description:
+ (RO) The amount of user data transferred (in bytes) inside each AoE
+ command on the network, network headers excluded.
--- /dev/null
+What: /sys/block/loopX/loop/autoclear
+Date: Aug, 2010
+KernelVersion: v2.6.37
+Contact: linux-block@vger.kernel.org
+Description:
+ (RO) Shows if the device is in autoclear mode or not ( "1" or
+ "0"). Autoclear (if set) indicates that the loopback device will
+ self-distruct after last close.
+
+What: /sys/block/loopX/loop/backing_file
+Date: Aug, 2010
+KernelVersion: v2.6.37
+Contact: linux-block@vger.kernel.org
+Description:
+ (RO) The path of the backing file that the loop device maps its
+ data blocks to.
+
+What: /sys/block/loopX/loop/offset
+Date: Aug, 2010
+KernelVersion: v2.6.37
+Contact: linux-block@vger.kernel.org
+Description:
+ (RO) Start offset (in bytes).
+
+What: /sys/block/loopX/loop/sizelimit
+Date: Aug, 2010
+KernelVersion: v2.6.37
+Contact: linux-block@vger.kernel.org
+Description:
+ (RO) The size (in bytes) that the block device maps, starting
+ from the offset.
+
+What: /sys/block/loopX/loop/partscan
+Date: Aug, 2011
+KernelVersion: v3.10
+Contact: linux-block@vger.kernel.org
+Description:
+ (RO) Shows if automatic partition scanning is enabled for the
+ device or not ("1" or "0"). This can be requested individually
+ per loop device during its setup by setting LO_FLAGS_PARTSCAN in
+ in the ioctl request. By default, no partition tables are
+ scanned.
+
+What: /sys/block/loopX/loop/dio
+Date: Aug, 2015
+KernelVersion: v4.10
+Contact: linux-block@vger.kernel.org
+Description:
+ (RO) Shows if direct IO is being used to access backing file or
+ not ("1 or "0").
--- /dev/null
+For all of the nmem device attributes under nfit/*, see the 'NVDIMM Firmware
+Interface Table (NFIT)' section in the ACPI specification
+(http://www.uefi.org/specifications) for more details.
+
+What: /sys/bus/nd/devices/nmemX/nfit/serial
+Date: Jun, 2015
+KernelVersion: v4.2
+Contact: linux-nvdimm@lists.01.org
+Description:
+ (RO) Serial number of the NVDIMM (non-volatile dual in-line
+ memory module), assigned by the module vendor.
+
+
+What: /sys/bus/nd/devices/nmemX/nfit/handle
+Date: Apr, 2015
+KernelVersion: v4.2
+Contact: linux-nvdimm@lists.01.org
+Description:
+ (RO) The address (given by the _ADR object) of the device on its
+ parent bus of the NVDIMM device containing the NVDIMM region.
+
+
+What: /sys/bus/nd/devices/nmemX/nfit/device
+Date: Apr, 2015
+KernelVersion: v4.1
+Contact: linux-nvdimm@lists.01.org
+Description:
+ (RO) Device id for the NVDIMM, assigned by the module vendor.
+
+
+What: /sys/bus/nd/devices/nmemX/nfit/rev_id
+Date: Jun, 2015
+KernelVersion: v4.2
+Contact: linux-nvdimm@lists.01.org
+Description:
+ (RO) Revision of the NVDIMM, assigned by the module vendor.
+
+
+What: /sys/bus/nd/devices/nmemX/nfit/phys_id
+Date: Apr, 2015
+KernelVersion: v4.2
+Contact: linux-nvdimm@lists.01.org
+Description:
+ (RO) Handle (i.e., instance number) for the SMBIOS (system
+ management BIOS) Memory Device structure describing the NVDIMM
+ containing the NVDIMM region.
+
+
+What: /sys/bus/nd/devices/nmemX/nfit/flags
+Date: Jun, 2015
+KernelVersion: v4.2
+Contact: linux-nvdimm@lists.01.org
+Description:
+ (RO) The flags in the NFIT memory device sub-structure indicate
+ the state of the data on the nvdimm relative to its energy
+ source or last "flush to persistence".
+
+ The attribute is a translation of the 'NVDIMM State Flags' field
+ in section 5.2.25.3 'NVDIMM Region Mapping' Structure of the
+ ACPI specification 6.2.
+
+ The health states are "save_fail", "restore_fail", "flush_fail",
+ "not_armed", "smart_event", "map_fail" and "smart_notify".
+
+
+What: /sys/bus/nd/devices/nmemX/nfit/format
+What: /sys/bus/nd/devices/nmemX/nfit/format1
+What: /sys/bus/nd/devices/nmemX/nfit/formats
+Date: Apr, 2016
+KernelVersion: v4.7
+Contact: linux-nvdimm@lists.01.org
+Description:
+ (RO) The interface codes indicate support for persistent memory
+ mapped directly into system physical address space and / or a
+ block aperture access mechanism to the NVDIMM media.
+ The 'formats' attribute displays the number of supported
+ interfaces.
+
+ This layout is compatible with existing libndctl binaries that
+ only expect one code per-dimm as they will ignore
+ nmemX/nfit/formats and nmemX/nfit/formatN.
+
+
+What: /sys/bus/nd/devices/nmemX/nfit/vendor
+Date: Apr, 2016
+KernelVersion: v4.7
+Contact: linux-nvdimm@lists.01.org
+Description:
+ (RO) Vendor id of the NVDIMM.
+
+
+What: /sys/bus/nd/devices/nmemX/nfit/dsm_mask
+Date: May, 2016
+KernelVersion: v4.7
+Contact: linux-nvdimm@lists.01.org
+Description:
+ (RO) The bitmask indicates the supported device specific control
+ functions relative to the NVDIMM command family supported by the
+ device
+
+
+What: /sys/bus/nd/devices/nmemX/nfit/family
+Date: Apr, 2016
+KernelVersion: v4.7
+Contact: linux-nvdimm@lists.01.org
+Description:
+ (RO) Displays the NVDIMM family command sets. Values
+ 0, 1, 2 and 3 correspond to NVDIMM_FAMILY_INTEL,
+ NVDIMM_FAMILY_HPE1, NVDIMM_FAMILY_HPE2 and NVDIMM_FAMILY_MSFT
+ respectively.
+
+ See the specifications for these command families here:
+ http://pmem.io/documents/NVDIMM_DSM_Interface-V1.6.pdf
+ https://github.com/HewlettPackard/hpe-nvm/blob/master/Documentation/
+ https://msdn.microsoft.com/library/windows/hardware/mt604741"
+
+
+What: /sys/bus/nd/devices/nmemX/nfit/id
+Date: Apr, 2016
+KernelVersion: v4.7
+Contact: linux-nvdimm@lists.01.org
+Description:
+ (RO) ACPI specification 6.2 section 5.2.25.9, defines an
+ identifier for an NVDIMM, which refelects the id attribute.
+
+
+What: /sys/bus/nd/devices/nmemX/nfit/subsystem_vendor
+Date: Apr, 2016
+KernelVersion: v4.7
+Contact: linux-nvdimm@lists.01.org
+Description:
+ (RO) Sub-system vendor id of the NVDIMM non-volatile memory
+ subsystem controller.
+
+
+What: /sys/bus/nd/devices/nmemX/nfit/subsystem_rev_id
+Date: Apr, 2016
+KernelVersion: v4.7
+Contact: linux-nvdimm@lists.01.org
+Description:
+ (RO) Sub-system revision id of the NVDIMM non-volatile memory subsystem
+ controller, assigned by the non-volatile memory subsystem
+ controller vendor.
+
+
+What: /sys/bus/nd/devices/nmemX/nfit/subsystem_device
+Date: Apr, 2016
+KernelVersion: v4.7
+Contact: linux-nvdimm@lists.01.org
+Description:
+ (RO) Sub-system device id for the NVDIMM non-volatile memory
+ subsystem controller, assigned by the non-volatile memory
+ subsystem controller vendor.
+
+
+What: /sys/bus/nd/devices/ndbusX/nfit/revision
+Date: Jun, 2015
+KernelVersion: v4.2
+Contact: linux-nvdimm@lists.01.org
+Description:
+ (RO) ACPI NFIT table revision number.
+
+
+What: /sys/bus/nd/devices/ndbusX/nfit/scrub
+Date: Sep, 2016
+KernelVersion: v4.9
+Contact: linux-nvdimm@lists.01.org
+Description:
+ (RW) This shows the number of full Address Range Scrubs (ARS)
+ that have been completed since driver load time. Userspace can
+ wait on this using select/poll etc. A '+' at the end indicates
+ an ARS is in progress
+
+ Writing a value of 1 triggers an ARS scan.
+
+
+What: /sys/bus/nd/devices/ndbusX/nfit/hw_error_scrub
+Date: Sep, 2016
+KernelVersion: v4.9
+Contact: linux-nvdimm@lists.01.org
+Description:
+ (RW) Provides a way to toggle the behavior between just adding
+ the address (cache line) where the MCE happened to the poison
+ list and doing a full scrub. The former (selective insertion of
+ the address) is done unconditionally.
+
+ This attribute can have the following values written to it:
+
+ '0': Switch to the default mode where an exception will only
+ insert the address of the memory error into the poison and
+ badblocks lists.
+ '1': Enable a full scrub to happen if an exception for a memory
+ error is received.
+
+
+What: /sys/bus/nd/devices/ndbusX/nfit/dsm_mask
+Date: Jun, 2017
+KernelVersion: v4.13
+Contact: linux-nvdimm@lists.01.org
+Description:
+ (RO) The bitmask indicates the supported bus specific control
+ functions. See the section named 'NVDIMM Root Device _DSMs' in
+ the ACPI specification.
+
+
+What: /sys/bus/nd/devices/regionX/nfit/range_index
+Date: Jun, 2015
+KernelVersion: v4.2
+Contact: linux-nvdimm@lists.01.org
+Description:
+ (RO) A unique number provided by the BIOS to identify an address
+ range. Used by NVDIMM Region Mapping Structure to uniquely refer
+ to this structure. Value of 0 is reserved and not used as an
+ index.
+
+
+What: /sys/bus/nd/devices/regionX/nfit/ecc_unit_size
+Date: Aug, 2017
+KernelVersion: v4.14
+Contact: linux-nvdimm@lists.01.org
+Description:
+ (RO) Size of a write request to a DIMM that will not incur a
+ read-modify-write cycle at the memory controller.
+
+ When the nfit driver initializes it runs an ARS (Address Range
+ Scrub) operation across every pmem range. Part of that process
+ involves determining the ARS capabilities of a given address
+ range. One of the capabilities that is reported is the 'Clear
+ Uncorrectable Error Range Length Unit Size' (see: ACPI 6.2
+ section 9.20.7.4 Function Index 1 - Query ARS Capabilities).
+ This property indicates the boundary at which the NVDIMM may
+ need to perform read-modify-write cycles to maintain ECC (Error
+ Correcting Code) blocks.
--- /dev/null
+What: /sys/bus/rapidio/devices/nn:d:iiii
+Description:
+ For each RapidIO device, the RapidIO subsystem creates files in
+ an individual subdirectory with the following name format of
+ device_name "nn:d:iiii", where:
+
+ nn - two-digit hexadecimal ID of RapidIO network where the
+ device resides
+ d - device type: 'e' - for endpoint or 's' - for switch
+ iiii - four-digit device destID for endpoints, or switchID for
+ switches
+
+ For example, below is a list of device directories that
+ represents a typical RapidIO network with one switch, one host,
+ and two agent endpoints, as it is seen by the enumerating host
+ (with destID = 1):
+
+ /sys/bus/rapidio/devices/00:e:0000
+ /sys/bus/rapidio/devices/00:e:0002
+ /sys/bus/rapidio/devices/00:s:0001
+
+ NOTE: An enumerating or discovering endpoint does not create a
+ sysfs entry for itself, this is why an endpoint with destID=1 is
+ not shown in the list.
+
+Attributes Common for All RapidIO Devices
+-----------------------------------------
+
+What: /sys/bus/rapidio/devices/nn:d:iiii/did
+Date: Nov, 2005
+KernelVersion: v2.6.15
+Contact: Matt Porter <mporter@kernel.crashing.org>,
+ Alexandre Bounine <alexandre.bounine@idt.com>
+Description:
+ (RO) returns the device identifier
+
+What: /sys/bus/rapidio/devices/nn:d:iiii/vid
+Date: Nov, 2005
+KernelVersion: v2.6.15
+Contact: Matt Porter <mporter@kernel.crashing.org>,
+ Alexandre Bounine <alexandre.bounine@idt.com>
+Description:
+ (RO) returns the device vendor identifier
+
+What: /sys/bus/rapidio/devices/nn:d:iiii/device_rev
+Date: Nov, 2005
+KernelVersion: v2.6.15
+Contact: Matt Porter <mporter@kernel.crashing.org>,
+ Alexandre Bounine <alexandre.bounine@idt.com>
+Description:
+ (RO) returns the device revision level
+
+What: /sys/bus/rapidio/devices/nn:d:iiii/asm_did
+Date: Nov, 2005
+KernelVersion: v2.6.15
+Contact: Matt Porter <mporter@kernel.crashing.org>,
+ Alexandre Bounine <alexandre.bounine@idt.com>
+Description:
+ (RO) returns identifier for the assembly containing the device
+
+What: /sys/bus/rapidio/devices/nn:d:iiii/asm_rev
+Date: Nov, 2005
+KernelVersion: v2.6.15
+Contact: Matt Porter <mporter@kernel.crashing.org>,
+ Alexandre Bounine <alexandre.bounine@idt.com>
+Description:
+ (RO) returns revision level of the assembly containing the
+ device
+
+What: /sys/bus/rapidio/devices/nn:d:iiii/asm_vid
+Date: Nov, 2005
+KernelVersion: v2.6.15
+Contact: Matt Porter <mporter@kernel.crashing.org>,
+ Alexandre Bounine <alexandre.bounine@idt.com>
+Description:
+ (RO) returns vendor identifier of the assembly containing the
+ device
+
+What: /sys/bus/rapidio/devices/nn:d:iiii/destid
+Date: Mar, 2011
+KernelVersion: v2.6.3
+Contact: Matt Porter <mporter@kernel.crashing.org>,
+ Alexandre Bounine <alexandre.bounine@idt.com>
+Description:
+ (RO) returns device destination ID assigned by the enumeration
+ routine
+
+What: /sys/bus/rapidio/devices/nn:d:iiii/lprev
+Date: Mar, 2011
+KernelVersion: v2.6.39
+Contact: Matt Porter <mporter@kernel.crashing.org>,
+ Alexandre Bounine <alexandre.bounine@idt.com>
+Description:
+ (RO) returns name of previous device (switch) on the path to the
+ device that that owns this attribute
+
+What: /sys/bus/rapidio/devices/nn:d:iiii/modalias
+Date: Jul, 2013
+KernelVersion: v3.11
+Contact: Matt Porter <mporter@kernel.crashing.org>,
+ Alexandre Bounine <alexandre.bounine@idt.com>
+Description:
+ (RO) returns the device modalias
+
+What: /sys/bus/rapidio/devices/nn:d:iiii/config
+Date: Nov, 2005
+KernelVersion: v2.6.15
+Contact: Matt Porter <mporter@kernel.crashing.org>,
+ Alexandre Bounine <alexandre.bounine@idt.com>
+Description:
+ (RW) Binary attribute to read from and write to the device
+ configuration registers using the RapidIO maintenance
+ transactions. This attribute is similar in behaviour to the
+ "config" attribute of PCI devices and provides an access to the
+ RapidIO device registers using standard file read and write
+ operations.
+
+RapidIO Switch Device Attributes
+--------------------------------
+
+RapidIO switches have additional attributes in sysfs. RapidIO subsystem supports
+common and device-specific sysfs attributes for switches. Because switches are
+integrated into the RapidIO subsystem, it offers a method to create
+device-specific sysfs attributes by specifying a callback function that may be
+set by the switch initialization routine during enumeration or discovery
+process.
+
+What: /sys/bus/rapidio/devices/nn:s:iiii/routes
+Date: Nov, 2005
+KernelVersion: v2.6.15
+Contact: Matt Porter <mporter@kernel.crashing.org>,
+ Alexandre Bounine <alexandre.bounine@idt.com>
+Description:
+ (RO) reports switch routing information in "destID port" format.
+ This attribute reports only valid routing table entries, one
+ line for each entry.
+
+What: /sys/bus/rapidio/devices/nn:s:iiii/destid
+Date: Mar, 2011
+KernelVersion: v2.6.3
+Contact: Matt Porter <mporter@kernel.crashing.org>,
+ Alexandre Bounine <alexandre.bounine@idt.com>
+Description:
+ (RO) device destination ID of the associated device that defines
+ a route to the switch
+
+What: /sys/bus/rapidio/devices/nn:s:iiii/hopcount
+Date: Mar, 2011
+KernelVersion: v2.6.39
+Contact: Matt Porter <mporter@kernel.crashing.org>,
+ Alexandre Bounine <alexandre.bounine@idt.com>
+Description:
+ (RO) number of hops on the path to the switch
+
+What: /sys/bus/rapidio/devices/nn:s:iiii/lnext
+Date: Mar, 2011
+KernelVersion: v2.6.39
+Contact: Matt Porter <mporter@kernel.crashing.org>,
+ Alexandre Bounine <alexandre.bounine@idt.com>
+Description:
+ (RO) returns names of devices linked to the switch except one of
+ a device linked to the ingress port (reported as "lprev"). This
+ is an array names with number of lines equal to number of ports
+ in switch. If a switch port has no attached device, returns
+ "null" instead of a device name.
+
+Device-specific Switch Attributes
+---------------------------------
+
+IDT_GEN2-
+
+What: /sys/bus/rapidio/devices/nn:s:iiii/errlog
+Date: Oct, 2010
+KernelVersion: v2.6.37
+Contact: Matt Porter <mporter@kernel.crashing.org>,
+ Alexandre Bounine <alexandre.bounine@idt.com>
+Description:
+ (RO) reads contents of device error log until it is empty.
+
+RapidIO Bus Attributes
+----------------------
+
+What: /sys/bus/rapidio/scan
+Date: May, 2013
+KernelVersion: v3.11
+Contact: Matt Porter <mporter@kernel.crashing.org>,
+ Alexandre Bounine <alexandre.bounine@idt.com>
+Description:
+ (WO) Allows to trigger enumeration discovery process from user
+ space. To initiate an enumeration or discovery process on
+ specific mport device, a user needs to write mport_ID (not
+ RapidIO destination ID) into this file. The mport_ID is a
+ sequential number (0 ... RIO_MAX_MPORTS) assigned to the mport
+ device. For example, for a machine with a single RapidIO
+ controller, mport_ID for that controller always will be 0. To
+ initiate RapidIO enumeration/discovery on all available mports a
+ user must write '-1' (or RIO_MPORT_ANY) into this attribute
+ file.
-What: /sys/bus/rbd/
-Date: November 2010
-Contact: Yehuda Sadeh <yehuda@newdream.net>,
- Sage Weil <sage@newdream.net>
+What: /sys/bus/rbd/add
+Date: Oct, 2010
+KernelVersion: v2.6.37
+Contact: Sage Weil <sage@newdream.net>
Description:
+ (WO) Add rbd block device.
-Being used for adding and removing rbd block devices.
+ Usage: <mon ip addr> <options> <pool name> <rbd image name> [<snap name>]
-Usage: <mon ip addr> <options> <pool name> <rbd image name> [<snap name>]
+ $ echo "192.168.0.1 name=admin rbd foo" > /sys/bus/rbd/add
- $ echo "192.168.0.1 name=admin rbd foo" > /sys/bus/rbd/add
+ The snapshot name can be "-" or omitted to map the image
+ read/write. A <dev-id> will be assigned for any registered block
+ device. If snapshot is used, it will be mapped read-only.
-The snapshot name can be "-" or omitted to map the image read/write. A <dev-id>
-will be assigned for any registered block device. If snapshot is used, it will
-be mapped read-only.
-Usage: <dev-id> [force]
+What: /sys/bus/rbd/remove
+Date: Oct, 2010
+KernelVersion: v2.6.37
+Contact: Sage Weil <sage@newdream.net>
+Description:
+ (WO) Remove rbd block device.
+
+ Usage: <dev-id> [force]
- $ echo 2 > /sys/bus/rbd/remove
+ $ echo 2 > /sys/bus/rbd/remove
+
+ Optional "force" argument which when passed will wait for
+ running requests and then unmap the image. Requests sent to the
+ driver after initiating the removal will be failed. (August
+ 2016, since 4.9.)
-Optional "force" argument which when passed will wait for running requests and
-then unmap the image. Requests sent to the driver after initiating the removal
-will be failed. (August 2016, since 4.9.)
What: /sys/bus/rbd/add_single_major
-Date: December 2013
-KernelVersion: 3.14
-Contact: Sage Weil <sage@inktank.com>
-Description: Available only if rbd module is inserted with single_major
+Date: Dec, 2013
+KernelVersion: v3.14
+Contact: Sage Weil <sage@newdream.net>
+Description:
+ (WO) Available only if rbd module is inserted with single_major
parameter set to true.
- Usage is the same as for /sys/bus/rbd/add. If present,
+
+ Usage is the same as for /sys/bus/rbd/add. If present, this
should be used instead of the latter: any attempts to use
- /sys/bus/rbd/add if /sys/bus/rbd/add_single_major is
- available will fail for backwards compatibility reasons.
+ /sys/bus/rbd/add if /sys/bus/rbd/add_single_major is available
+ will fail for backwards compatibility reasons.
+
What: /sys/bus/rbd/remove_single_major
-Date: December 2013
-KernelVersion: 3.14
-Contact: Sage Weil <sage@inktank.com>
-Description: Available only if rbd module is inserted with single_major
+Date: Dec, 2013
+KernelVersion: v3.14
+Contact: Sage Weil <sage@newdream.net>
+Description:
+ (WO) Available only if rbd module is inserted with single_major
parameter set to true.
- Usage is the same as for /sys/bus/rbd/remove. If present,
+
+ Usage is the same as for /sys/bus/rbd/remove. If present, this
should be used instead of the latter: any attempts to use
/sys/bus/rbd/remove if /sys/bus/rbd/remove_single_major is
available will fail for backwards compatibility reasons.
-Entries under /sys/bus/rbd/devices/<dev-id>/
---------------------------------------------
-
-client_addr
-
- The ceph unique client entity_addr_t (address + nonce).
- The format is <address>:<port>/<nonce>: '1.2.3.4:1234/5678' or
- '[1:2:3:4:5:6:7:8]:1234/5678'. (August 2016, since 4.9.)
-
-client_id
-
- The ceph unique client id that was assigned for this specific session.
-
-cluster_fsid
- The ceph cluster UUID. (August 2016, since 4.9.)
-
-config_info
-
- The string written into /sys/bus/rbd/add{,_single_major}. (August
- 2016, since 4.9.)
-
-features
-
- A hexadecimal encoding of the feature bits for this image.
-
-major
-
- The block device major number.
+What: /sys/bus/rbd/supported_features
+Date: Mar, 2017
+KernelVersion: v4.11
+Contact: Sage Weil <sage@newdream.net>
+Description:
+ (RO) Displays the features supported by the rbd module so that
+ userspace can generate meaningful error messages and spell out
+ unsupported features that need to be disabled.
+
+
+What: /sys/bus/rbd/devices/<dev-id>/size
+What: /sys/bus/rbd/devices/<dev-id>/major
+What: /sys/bus/rbd/devices/<dev-id>/client_id
+What: /sys/bus/rbd/devices/<dev-id>/pool
+What: /sys/bus/rbd/devices/<dev-id>/name
+What: /sys/bus/rbd/devices/<dev-id>/refresh
+What: /sys/bus/rbd/devices/<dev-id>/current_snap
+Date: Oct, 2010
+KernelVersion: v2.6.37
+Contact: Sage Weil <sage@newdream.net>
+Description:
+ size: (RO) The size (in bytes) of the mapped block
+ device.
-minor
+ major: (RO) The block device major number.
- The block device minor number. (December 2013, since 3.14.)
+ client_id: (RO) The ceph unique client id that was assigned
+ for this specific session.
-name
+ pool: (RO) The name of the storage pool where this rbd
+ image resides. An rbd image name is unique
+ within its pool.
- The name of the rbd image.
+ name: (RO) The name of the rbd image.
-image_id
+ refresh: (WO) Writing to this file will reread the image
+ header data and set all relevant data structures
+ accordingly.
- The unique id for the rbd image. (For rbd image format 1
- this is empty.)
+ current_snap: (RO) The current snapshot for which the device
+ is mapped.
-pool
- The name of the storage pool where this rbd image resides.
- An rbd image name is unique within its pool.
+What: /sys/bus/rbd/devices/<dev-id>/pool_id
+Date: Jul, 2012
+KernelVersion: v3.6
+Contact: Sage Weil <sage@newdream.net>
+Description:
+ (RO) The unique identifier for the rbd image's pool. This is a
+ permanent attribute of the pool. A pool's id will never change.
-pool_id
- The unique identifier for the rbd image's pool. This is
- a permanent attribute of the pool. A pool's id will never
- change.
+What: /sys/bus/rbd/devices/<dev-id>/image_id
+What: /sys/bus/rbd/devices/<dev-id>/features
+Date: Oct, 2012
+KernelVersion: v3.7
+Contact: Sage Weil <sage@newdream.net>
+Description:
+ image_id: (RO) The unique id for the rbd image. (For rbd
+ image format 1 this is empty.)
-size
+ features: (RO) A hexadecimal encoding of the feature bits
+ for this image.
- The size (in bytes) of the mapped block device.
-refresh
+What: /sys/bus/rbd/devices/<dev-id>/parent
+Date: Nov, 2012
+KernelVersion: v3.8
+Contact: Sage Weil <sage@newdream.net>
+Description:
+ (RO) Information identifying the chain of parent images in a
+ layered rbd image. Entries are separated by empty lines.
- Writing to this file will reread the image header data and set
- all relevant datastructures accordingly.
-current_snap
+What: /sys/bus/rbd/devices/<dev-id>/minor
+Date: Dec, 2013
+KernelVersion: v3.14
+Contact: Sage Weil <sage@newdream.net>
+Description:
+ (RO) The block device minor number.
- The current snapshot for which the device is mapped.
-snap_id
+What: /sys/bus/rbd/devices/<dev-id>/snap_id
+What: /sys/bus/rbd/devices/<dev-id>/config_info
+What: /sys/bus/rbd/devices/<dev-id>/cluster_fsid
+What: /sys/bus/rbd/devices/<dev-id>/client_addr
+Date: Aug, 2016
+KernelVersion: v4.9
+Contact: Sage Weil <sage@newdream.net>
+Description:
+ snap_id: (RO) The current snapshot's id.
- The current snapshot's id. (August 2016, since 4.9.)
+ config_info: (RO) The string written into
+ /sys/bus/rbd/add{,_single_major}.
-parent
+ cluster_fsid: (RO) The ceph cluster UUID.
- Information identifying the chain of parent images in a layered rbd
- image. Entries are separated by empty lines.
+ client_addr: (RO) The ceph unique client
+ entity_addr_t (address + nonce). The format is
+ <address>:<port>/<nonce>: '1.2.3.4:1234/5678' or
+ '[1:2:3:4:5:6:7:8]:1234/5678'.
--- /dev/null
+sysfs interface for analog devices adp5520(01) backlight driver
+---------------------------------------------------------------
+
+The backlight brightness control operates at three different levels for the
+adp5520 and adp5501 devices: daylight (level 1), office (level 2) and dark
+(level 3). By default the brightness operates at the daylight brightness level.
+
+What: /sys/class/backlight/<backlight>/daylight_max
+What: /sys/class/backlight/<backlight>/office_max
+What: /sys/class/backlight/<backlight>/dark_max
+Date: Sep, 2009
+KernelVersion: v2.6.32
+Contact: Michael Hennerich <michael.hennerich@analog.com>
+Description:
+ (RW) Maximum current setting for the backlight when brightness
+ is at one of the three levels (daylight, office or dark). This
+ is an input code between 0 and 127, which is transformed to a
+ value between 0 mA and 30 mA using linear or non-linear
+ algorithms.
+
+What: /sys/class/backlight/<backlight>/daylight_dim
+What: /sys/class/backlight/<backlight>/office_dim
+What: /sys/class/backlight/<backlight>/dark_dim
+Date: Sep, 2009
+KernelVersion: v2.6.32
+Contact: Michael Hennerich <michael.hennerich@analog.com>
+Description:
+ (RW) Dim current setting for the backlight when brightness is at
+ one of the three levels (daylight, office or dark). This is an
+ input code between 0 and 127, which is transformed to a value
+ between 0 mA and 30 mA using linear or non-linear algorithms.
--- /dev/null
+sysfs interface for analog devices adp8860 backlight driver
+-----------------------------------------------------------
+
+The backlight brightness control operates at three different levels for the
+adp8860, adp8861 and adp8863 devices: daylight (level 1), office (level 2) and
+dark (level 3). By default the brightness operates at the daylight brightness
+level.
+
+What: /sys/class/backlight/<backlight>/ambient_light_level
+Date: Apr, 2010
+KernelVersion: v2.6.35
+Contact: Michael Hennerich <michael.hennerich@analog.com>
+Description:
+ (RO) 13-bit conversion value for the first light sensor—high
+ byte (Bit 12 to Bit 8). The value is updated every 80 ms (when
+ the light sensor is enabled).
+
+
+What: /sys/class/backlight/<backlight>/ambient_light_zone
+Date: Apr, 2010
+KernelVersion: v2.6.35
+Contact: Michael Hennerich <michael.hennerich@analog.com>
+Description:
+ (RW) Read or write the specific level at which the backlight
+ operates. Value "0" enables automatic ambient light sensing, and
+ values "1", "2" or "3" set the control to daylight, office or
+ dark respectively.
+
+
+What: /sys/class/backlight/<backlight>/l1_daylight_max
+What: /sys/class/backlight/<backlight>/l2_office_max
+What: /sys/class/backlight/<backlight>/l3_dark_max
+Date: Apr, 2010
+KernelVersion: v2.6.35
+Contact: Michael Hennerich <michael.hennerich@analog.com>
+Description:
+ (RW) Maximum current setting for the backlight when brightness
+ is at one of the three levels (daylight, office or dark). This
+ is an input code between 0 and 127, which is transformed to a
+ value between 0 mA and 30 mA using linear or non-linear
+ algorithms.
+
+
+What: /sys/class/backlight/<backlight>/l1_daylight_dim
+What: /sys/class/backlight/<backlight>/l2_office_dim
+What: /sys/class/backlight/<backlight>/l3_dark_dim
+Date: Apr, 2010
+KernelVersion: v2.6.35
+Contact: Michael Hennerich <michael.hennerich@analog.com>
+Description:
+ (RW) Dim current setting for the backlight when brightness is at
+ one of the three levels (daylight, office or dark). This is an
+ input code between 0 and 127, which is transformed to a value
+ between 0 mA and 30 mA using linear or non-linear algorithms.
--- /dev/null
+sysfs interface for Texas Instruments lm3639 backlight + flash led driver chip
+------------------------------------------------------------------------------
+
+What: /sys/class/backlight/<backlight>/bled_mode
+Date: Oct, 2012
+KernelVersion: v3.10
+Contact: dri-devel@lists.freedesktop.org
+Description:
+ (WO) Write to the backlight mapping mode. The backlight current
+ can be mapped for either exponential (value "0") or linear
+ mapping modes (default).
--- /dev/null
+What: /sys/class/bsr/bsr*/bsr_size
+Date: Jul, 2008
+KernelVersion: 2.6.27
+Contact: Arnd Bergmann <arnd@arndb.de>,
+ Greg Kroah-Hartman <gregkh@linuxfoundation.org>
+Description:
+ (RO) Size of the barrier-synchronization register (BSR)
+ register in bytes.
+
+What: /sys/class/bsr/bsr*/bsr_length
+Date: Jul, 2008
+KernelVersion: 2.6.27
+Contact: Arnd Bergmann <arnd@arndb.de>,
+ Greg Kroah-Hartman <gregkh@linuxfoundation.org>
+Description:
+ (RO) The length of memory region that can be mapped in bytes.
+
+What: /sys/class/bsr/bsr*/bsr_stride
+Date: Jul, 2008
+KernelVersion: 2.6.27
+Contact: Arnd Bergmann <arnd@arndb.de>,
+ Greg Kroah-Hartman <gregkh@linuxfoundation.org>
+Description:
+ (RO) The stride or the interval at which the allocated BSR bytes
+ repeat within the mapping.
+++ /dev/null
-What: /sys/class/infiniband/<hca>/ports/<port-number>/gid_attrs/ndevs/<gid-index>
-Date: November 29, 2015
-KernelVersion: 4.4.0
-Contact: linux-rdma@vger.kernel.org
-Description: The net-device's name associated with the GID resides
- at index <gid-index>.
-
-What: /sys/class/infiniband/<hca>/ports/<port-number>/gid_attrs/types/<gid-index>
-Date: November 29, 2015
-KernelVersion: 4.4.0
-Contact: linux-rdma@vger.kernel.org
-Description: The RoCE type of the associated GID resides at index <gid-index>.
- This could either be "IB/RoCE v1" for IB and RoCE v1 based GODs
- or "RoCE v2" for RoCE v2 based GIDs.
-
-
--- /dev/null
+sysfs interface for the S6E63M0 AMOLED LCD panel driver
+-------------------------------------------------------
+
+What: /sys/class/lcd/<lcd>/gamma_mode
+Date: May, 2010
+KernelVersion: v2.6.35
+Contact: dri-devel@lists.freedesktop.org
+Description:
+ (RW) Read or write the gamma mode. Following three modes are
+ supported:
+ 0 - gamma value 2.2,
+ 1 - gamma value 1.9 and
+ 2 - gamma value 1.7.
+
+
+What: /sys/class/lcd/<lcd>/gamma_table
+Date: May, 2010
+KernelVersion: v2.6.35
+Contact: dri-devel@lists.freedesktop.org
+Description:
+ (RO) Displays the size of the gamma table i.e. the number of
+ gamma modes available.
+
+This is a backlight lcd driver. These interfaces are an extension to the API
+documented in Documentation/ABI/testing/sysfs-class-lcd and in
+Documentation/ABI/stable/sysfs-class-backlight (under
+/sys/class/backlight/<backlight>/).
-What: /sys/class/pktcdvd/
-Date: Oct. 2006
-KernelVersion: 2.6.20
-Contact: Thomas Maier <balagi@justmail.de>
-Description:
-
sysfs interface
---------------
+The pktcdvd module (packet writing driver) creates the following files in the
+sysfs: (<devid> is in the format major:minor)
+
+What: /sys/class/pktcdvd/add
+What: /sys/class/pktcdvd/remove
+What: /sys/class/pktcdvd/device_map
+Date: Oct. 2006
+KernelVersion: 2.6.20
+Contact: Thomas Maier <balagi@justmail.de>
+Description:
+
+ add: (WO) Write a block device id (major:minor) to
+ create a new pktcdvd device and map it to the
+ block device.
+
+ remove: (WO) Write the pktcdvd device id (major:minor)
+ to remove the pktcdvd device.
+
+ device_map: (RO) Shows the device mapping in format:
+ pktcdvd[0-7] <pktdevid> <blkdevid>
+
+
+What: /sys/class/pktcdvd/pktcdvd[0-7]/dev
+What: /sys/class/pktcdvd/pktcdvd[0-7]/uevent
+Date: Oct. 2006
+KernelVersion: 2.6.20
+Contact: Thomas Maier <balagi@justmail.de>
+Description:
+ dev: (RO) Device id
+
+ uevent: (WO) To send a uevent
+
+
+What: /sys/class/pktcdvd/pktcdvd[0-7]/stat/packets_started
+What: /sys/class/pktcdvd/pktcdvd[0-7]/stat/packets_finished
+What: /sys/class/pktcdvd/pktcdvd[0-7]/stat/kb_written
+What: /sys/class/pktcdvd/pktcdvd[0-7]/stat/kb_read
+What: /sys/class/pktcdvd/pktcdvd[0-7]/stat/kb_read_gather
+What: /sys/class/pktcdvd/pktcdvd[0-7]/stat/reset
+Date: Oct. 2006
+KernelVersion: 2.6.20
+Contact: Thomas Maier <balagi@justmail.de>
+Description:
+ packets_started: (RO) Number of started packets.
+
+ packets_finished: (RO) Number of finished packets.
+
+ kb_written: (RO) kBytes written.
+
+ kb_read: (RO) kBytes read.
+
+ kb_read_gather: (RO) kBytes read to fill write packets.
+
+ reset: (WO) Write any value to it to reset
+ pktcdvd device statistic values, like
+ bytes read/written.
+
+
+What: /sys/class/pktcdvd/pktcdvd[0-7]/write_queue/size
+What: /sys/class/pktcdvd/pktcdvd[0-7]/write_queue/congestion_off
+What: /sys/class/pktcdvd/pktcdvd[0-7]/write_queue/congestion_on
+Date: Oct. 2006
+KernelVersion: 2.6.20
+Contact: Thomas Maier <balagi@justmail.de>
+Description:
+ size: (RO) Contains the size of the bio write queue.
+
+ congestion_off: (RW) If bio write queue size is below this mark,
+ accept new bio requests from the block layer.
-The pktcdvd module (packet writing driver) creates
-these files in the sysfs:
-(<devid> is in format major:minor )
-
-/sys/class/pktcdvd/
- add (0200) Write a block device id (major:minor)
- to create a new pktcdvd device and map
- it to the block device.
-
- remove (0200) Write the pktcdvd device id (major:minor)
- to it to remove the pktcdvd device.
-
- device_map (0444) Shows the device mapping in format:
- pktcdvd[0-7] <pktdevid> <blkdevid>
-
-/sys/class/pktcdvd/pktcdvd[0-7]/
- dev (0444) Device id
- uevent (0200) To send an uevent.
-
-/sys/class/pktcdvd/pktcdvd[0-7]/stat/
- packets_started (0444) Number of started packets.
- packets_finished (0444) Number of finished packets.
-
- kb_written (0444) kBytes written.
- kb_read (0444) kBytes read.
- kb_read_gather (0444) kBytes read to fill write packets.
-
- reset (0200) Write any value to it to reset
- pktcdvd device statistic values, like
- bytes read/written.
-
-/sys/class/pktcdvd/pktcdvd[0-7]/write_queue/
- size (0444) Contains the size of the bio write
- queue.
-
- congestion_off (0644) If bio write queue size is below
- this mark, accept new bio requests
- from the block layer.
-
- congestion_on (0644) If bio write queue size is higher
- as this mark, do no longer accept
- bio write requests from the block
- layer and wait till the pktcdvd
- device has processed enough bio's
- so that bio write queue size is
- below congestion off mark.
- A value of <= 0 disables congestion
- control.
+ congestion_on: (RW) If bio write queue size is higher as this
+ mark, do no longer accept bio write requests
+ from the block layer and wait till the pktcdvd
+ device has processed enough bio's so that bio
+ write queue size is below congestion off mark.
+ A value of <= 0 disables congestion control.
Example:
--- /dev/null
+What: /sys/class/rapidio_port
+Description:
+ On-chip RapidIO controllers and PCIe-to-RapidIO bridges
+ (referenced as "Master Port" or "mport") are presented in sysfs
+ as the special class of devices: "rapidio_port".
+ The /sys/class/rapidio_port subdirectory contains individual
+ subdirectories named as "rapidioN" where N = mport ID registered
+ with RapidIO subsystem.
+ NOTE: An mport ID is not a RapidIO destination ID assigned to a
+ given local mport device.
+
+What: /sys/class/rapidio_port/rapidioN/sys_size
+Date: Apr, 2014
+KernelVersion: v3.15
+Contact: Matt Porter <mporter@kernel.crashing.org>,
+ Alexandre Bounine <alexandre.bounine@idt.com>
+Description:
+ (RO) reports RapidIO common transport system size:
+ 0 = small (8-bit destination ID, max. 256 devices),
+ 1 = large (16-bit destination ID, max. 65536 devices).
+
+What: /sys/class/rapidio_port/rapidioN/port_destid
+Date: Apr, 2014
+KernelVersion: v3.15
+Contact: Matt Porter <mporter@kernel.crashing.org>,
+ Alexandre Bounine <alexandre.bounine@idt.com>
+Description:
+ (RO) reports RapidIO destination ID assigned to the given
+ RapidIO mport device. If value 0xFFFFFFFF is returned this means
+ that no valid destination ID have been assigned to the mport
+ (yet). Normally, before enumeration/discovery have been executed
+ only fabric enumerating mports have a valid destination ID
+ assigned to them using "hdid=..." rapidio module parameter.
+
+After enumeration or discovery was performed for a given mport device,
+the corresponding subdirectory will also contain subdirectories for each
+child RapidIO device connected to the mport.
+
+The example below shows mport device subdirectory with several child RapidIO
+devices attached to it.
+
+[rio@rapidio ~]$ ls /sys/class/rapidio_port/rapidio0/ -l
+total 0
+drwxr-xr-x 3 root root 0 Feb 11 15:10 00:e:0001
+drwxr-xr-x 3 root root 0 Feb 11 15:10 00:e:0004
+drwxr-xr-x 3 root root 0 Feb 11 15:10 00:e:0007
+drwxr-xr-x 3 root root 0 Feb 11 15:10 00:s:0002
+drwxr-xr-x 3 root root 0 Feb 11 15:10 00:s:0003
+drwxr-xr-x 3 root root 0 Feb 11 15:10 00:s:0005
+lrwxrwxrwx 1 root root 0 Feb 11 15:11 device -> ../../../0000:01:00.0
+-r--r--r-- 1 root root 4096 Feb 11 15:11 port_destid
+drwxr-xr-x 2 root root 0 Feb 11 15:11 power
+lrwxrwxrwx 1 root root 0 Feb 11 15:04 subsystem -> ../../../../../../class/rapidio_port
+-r--r--r-- 1 root root 4096 Feb 11 15:11 sys_size
+-rw-r--r-- 1 root root 4096 Feb 11 15:04 uevent
--- /dev/null
+What: /sys/devices/platform/i8042/.../sensitivity
+Date: Aug, 2005
+KernelVersion: 2.6.14
+Contact: linux-input@vger.kernel.org
+Description:
+ (RW) Trackpoint sensitivity.
+
+What: /sys/devices/platform/i8042/.../intertia
+Date: Aug, 2005
+KernelVersion: 2.6.14
+Contact: linux-input@vger.kernel.org
+Description:
+ (RW) Negative inertia factor. High values cause the cursor to
+ snap backward when the trackpoint is released.
+
+What: /sys/devices/platform/i8042/.../reach
+Date: Aug, 2005
+KernelVersion: 2.6.14
+Contact: linux-input@vger.kernel.org
+Description:
+ (RW) Backup range for z-axis press.
+
+What: /sys/devices/platform/i8042/.../draghys
+Date: Aug, 2005
+KernelVersion: 2.6.14
+Contact: linux-input@vger.kernel.org
+Description:
+ (RW) The drag hysteresis controls how hard it is to drag with
+ z-axis pressed.
+
+What: /sys/devices/platform/i8042/.../mindrag
+Date: Aug, 2005
+KernelVersion: 2.6.14
+Contact: linux-input@vger.kernel.org
+Description:
+ (RW) Minimum amount of force needed to trigger dragging.
+
+What: /sys/devices/platform/i8042/.../speed
+Date: Aug, 2005
+KernelVersion: 2.6.14
+Contact: linux-input@vger.kernel.org
+Description:
+ (RW) Speed of the trackpoint cursor.
+
+What: /sys/devices/platform/i8042/.../thresh
+Date: Aug, 2005
+KernelVersion: 2.6.14
+Contact: linux-input@vger.kernel.org
+Description:
+ (RW) Minimum value for z-axis force required to trigger a press
+ or release, relative to the running average.
+
+What: /sys/devices/platform/i8042/.../upthresh
+Date: Aug, 2005
+KernelVersion: 2.6.14
+Contact: linux-input@vger.kernel.org
+Description:
+ (RW) The offset from the running average required to generate a
+ select (click) on z-axis on release.
+
+What: /sys/devices/platform/i8042/.../ztime
+Date: Aug, 2005
+KernelVersion: 2.6.14
+Contact: linux-input@vger.kernel.org
+Description:
+ (RW) This attribute determines how sharp a press has to be in
+ order to be recognized.
+
+What: /sys/devices/platform/i8042/.../jenks
+Date: Aug, 2005
+KernelVersion: 2.6.14
+Contact: linux-input@vger.kernel.org
+Description:
+ (RW) Minimum curvature in degrees required to generate a double
+ click without a release.
+
+What: /sys/devices/platform/i8042/.../skipback
+Date: Aug, 2005
+KernelVersion: 2.6.14
+Contact: linux-input@vger.kernel.org
+Description:
+ (RW) When the skipback bit is set, backup cursor movement during
+ releases from drags will be suppressed. The default value for
+ this bit is 0.
+
+What: /sys/devices/platform/i8042/.../ext_dev
+Date: Aug, 2005
+KernelVersion: 2.6.14
+Contact: linux-input@vger.kernel.org
+Description:
+ (RW) Disable (0) or enable (1) external pointing device.
+
+What: /sys/devices/platform/i8042/.../press_to_select
+Date: Aug, 2005
+KernelVersion: 2.6.14
+Contact: linux-input@vger.kernel.org
+Description:
+ (RW) Writing a value of 1 to this file will enable the Press to
+ Select functions like tapping the control stick to simulate a
+ left click, and writing 0 will disable it.
+
+What: /sys/devices/platform/i8042/.../drift_time
+Date: Dec, 2014
+KernelVersion: 3.19
+Contact: linux-input@vger.kernel.org
+Description:
+ (RW) This parameter controls the period of time to test for a
+ ‘hands off’ condition (i.e. when no force is applied) before a
+ drift (noise) calibration occurs.
+
+ IBM Trackpoints have a feature to compensate for drift by
+ recalibrating themselves periodically. By default, if for 0.5
+ seconds there is no change in position, it's used as the new
+ zero. This duration is too low. Often, the calibration happens
+ when the trackpoint is in fact being used.
"make localyesconfig" Similar to localmodconfig, except it will convert
all module options to built in (=y) options.
+ "make kvmconfig" Enable additional options for kvm guest kernel support.
+
+ "make xenconfig" Enable additional options for xen dom0 guest kernel
+ support.
+
+ "make tinyconfig" Configure the tiniest possible kernel.
+
You can find more information on using the Linux kernel config tools
in Documentation/kbuild/kconfig.txt.
=========================
The kernel contains a ring of public keys that can be viewed by root. They're
-in a keyring called ".system_keyring" that can be seen by::
+in a keyring called ".builtin_trusted_keys" that can be seen by::
[root@deneb ~]# cat /proc/keys
...
- 223c7853 I------ 1 perm 1f030000 0 0 keyring .system_keyring: 1
+ 223c7853 I------ 1 perm 1f030000 0 0 keyring .builtin_trusted_keys: 1
302d2d52 I------ 1 perm 1f010000 0 0 asymmetri Fedora kernel signing key: d69a84e6bce3d216b979e9505b3e3ef9a7118079: X509.RSA a7118079 []
...
Finally, it is possible to add additional public keys by doing::
- keyctl padd asymmetric "" [.system_keyring-ID] <[key-file]
+ keyctl padd asymmetric "" [.builtin_trusted_keys-ID] <[key-file]
e.g.::
keyctl padd asymmetric "" 0x223c7853 <my_public_key.x509
Note, however, that the kernel will only permit keys to be added to
-``.system_keyring _if_`` the new key's X.509 wrapper is validly signed by a key
-that is already resident in the .system_keyring at the time the key was added.
+``.builtin_trusted_keys`` **if** the new key's X.509 wrapper is validly signed by a key
+that is already resident in the ``.builtin_trusted_keys`` at the time the key was added.
========================
Disclosure
----------
-The goal of the Linux kernel security team is to work with the
-bug submitter to bug resolution as well as disclosure. We prefer
-to fully disclose the bug as soon as possible. It is reasonable to
-delay disclosure when the bug or the fix is not yet fully understood,
-the solution is not well-tested or for vendor coordination. However, we
-expect these delays to be short, measurable in days, not weeks or months.
-A disclosure date is negotiated by the security team working with the
-bug submitter as well as vendors. However, the kernel security team
-holds the final say when setting a disclosure date. The timeframe for
-disclosure is from immediate (esp. if it's already publicly known)
+The goal of the Linux kernel security team is to work with the bug
+submitter to understand and fix the bug. We prefer to publish the fix as
+soon as possible, but try to avoid public discussion of the bug itself
+and leave that to others.
+
+Publishing the fix may be delayed when the bug or the fix is not yet
+fully understood, the solution is not well-tested or for vendor
+coordination. However, we expect these delays to be short, measurable in
+days, not weeks or months. A release date is negotiated by the security
+team working with the bug submitter as well as vendors. However, the
+kernel security team holds the final say when setting a timeframe. The
+timeframe varies from immediate (esp. if it's already publicly known bug)
to a few weeks. As a basic default policy, we expect report date to
-disclosure date to be on the order of 7 days.
+release date to be on the order of 7 days.
Coordination
------------
mechanism. The string is followed by a series of position-sensitive
characters, each representing a particular tainted value.
- 1) 'G' if all modules loaded have a GPL or compatible license, 'P' if
+ 1) ``G`` if all modules loaded have a GPL or compatible license, ``P`` if
any proprietary module has been loaded. Modules without a
MODULE_LICENSE or with a MODULE_LICENSE that is not recognised by
insmod as GPL compatible are assumed to be proprietary.
- 2) ``F`` if any module was force loaded by ``insmod -f``, ``' '`` if all
+ 2) ``F`` if any module was force loaded by ``insmod -f``, ``' '`` if all
modules were loaded normally.
- 3) ``S`` if the oops occurred on an SMP kernel running on hardware that
+ 3) ``S`` if the oops occurred on an SMP kernel running on hardware that
hasn't been certified as safe to run multiprocessor.
Currently this occurs only on various Athlons that are not
SMP capable.
- 4) ``R`` if a module was force unloaded by ``rmmod -f``, ``' '`` if all
+ 4) ``R`` if a module was force unloaded by ``rmmod -f``, ``' '`` if all
modules were unloaded normally.
- 5) ``M`` if any processor has reported a Machine Check Exception,
+ 5) ``M`` if any processor has reported a Machine Check Exception,
``' '`` if no Machine Check Exceptions have occurred.
- 6) ``B`` if a page-release function has found a bad page reference or
+ 6) ``B`` if a page-release function has found a bad page reference or
some unexpected page flags.
- 7) ``U`` if a user or user application specifically requested that the
+ 7) ``U`` if a user or user application specifically requested that the
Tainted flag be set, ``' '`` otherwise.
- 8) ``D`` if the kernel has died recently, i.e. there was an OOPS or BUG.
+ 8) ``D`` if the kernel has died recently, i.e. there was an OOPS or BUG.
- 9) ``A`` if the ACPI table has been overridden.
+ 9) ``A`` if the ACPI table has been overridden.
10) ``W`` if a warning has previously been issued by the kernel.
(Though some warnings may set more specific taint flags.)
Pointers printed without a specifier extension (i.e unadorned %p) are
hashed to prevent leaking information about the kernel memory layout. This
has the added benefit of providing a unique identifier. On 64-bit machines
-the first 32 bits are zeroed. If you *really* want the address see %px
-below.
+the first 32 bits are zeroed. The kernel will print ``(ptrval)`` until it
+gathers enough entropy. If you *really* want the address see %px below.
Symbols/Function Pointers
-------------------------
If the function enters and exits without the lock held, acquiring and
releasing the lock inside the function in a balanced way, no
-annotation is needed. The tree annotations above are for cases where
+annotation is needed. The three annotations above are for cases where
sparse would otherwise report a context imbalance.
Getting sparse
-Including kernel-doc comments
-=============================
-
-The Linux kernel source files may contain structured documentation comments, or
-kernel-doc comments to describe the functions and types and design of the
-code. The documentation comments may be included to any of the reStructuredText
-documents using a dedicated kernel-doc Sphinx directive extension.
-
-The kernel-doc directive is of the format::
-
- .. kernel-doc:: source
- :option:
-
-The *source* is the path to a source file, relative to the kernel source
-tree. The following directive options are supported:
-
-export: *[source-pattern ...]*
- Include documentation for all functions in *source* that have been exported
- using ``EXPORT_SYMBOL`` or ``EXPORT_SYMBOL_GPL`` either in *source* or in any
- of the files specified by *source-pattern*.
-
- The *source-pattern* is useful when the kernel-doc comments have been placed
- in header files, while ``EXPORT_SYMBOL`` and ``EXPORT_SYMBOL_GPL`` are next to
- the function definitions.
-
- Examples::
-
- .. kernel-doc:: lib/bitmap.c
- :export:
-
- .. kernel-doc:: include/net/mac80211.h
- :export: net/mac80211/*.c
-
-internal: *[source-pattern ...]*
- Include documentation for all functions and types in *source* that have
- **not** been exported using ``EXPORT_SYMBOL`` or ``EXPORT_SYMBOL_GPL`` either
- in *source* or in any of the files specified by *source-pattern*.
-
- Example::
-
- .. kernel-doc:: drivers/gpu/drm/i915/intel_audio.c
- :internal:
-
-doc: *title*
- Include documentation for the ``DOC:`` paragraph identified by *title* in
- *source*. Spaces are allowed in *title*; do not quote the *title*. The *title*
- is only used as an identifier for the paragraph, and is not included in the
- output. Please make sure to have an appropriate heading in the enclosing
- reStructuredText document.
-
- Example::
-
- .. kernel-doc:: drivers/gpu/drm/i915/intel_audio.c
- :doc: High Definition Audio over HDMI and Display Port
-
-functions: *function* *[...]*
- Include documentation for each *function* in *source*.
-
- Example::
-
- .. kernel-doc:: lib/bitmap.c
- :functions: bitmap_parselist bitmap_parselist_user
-
-Without options, the kernel-doc directive includes all documentation comments
-from the source file.
-
-The kernel-doc extension is included in the kernel source tree, at
-``Documentation/sphinx/kerneldoc.py``. Internally, it uses the
-``scripts/kernel-doc`` script to extract the documentation comments from the
-source.
-
-.. _kernel_doc:
-
Writing kernel-doc comments
===========================
-In order to provide embedded, "C" friendly, easy to maintain, but consistent and
-extractable overview, function and type documentation, the Linux kernel has
-adopted a consistent style for documentation comments. The format for this
-documentation is called the kernel-doc format, described below. This style
-embeds the documentation within the source files, using a few simple conventions
-for adding documentation paragraphs and documenting functions and their
-parameters, structures and unions and their members, enumerations, and typedefs.
-
-.. note:: The kernel-doc format is deceptively similar to gtk-doc or Doxygen,
- yet distinctively different, for historical reasons. The kernel source
- contains tens of thousands of kernel-doc comments. Please stick to the style
- described here.
+The Linux kernel source files may contain structured documentation
+comments in the kernel-doc format to describe the functions, types
+and design of the code. It is easier to keep documentation up-to-date
+when it is embedded in source files.
-The ``scripts/kernel-doc`` script is used by the Sphinx kernel-doc extension in
-the documentation build to extract this embedded documentation into the various
-HTML, PDF, and other format documents.
-
-In order to provide good documentation of kernel functions and data structures,
-please use the following conventions to format your kernel-doc comments in the
-Linux kernel source.
-
-How to format kernel-doc comments
----------------------------------
+.. note:: The kernel-doc format is deceptively similar to javadoc,
+ gtk-doc or Doxygen, yet distinctively different, for historical
+ reasons. The kernel source contains tens of thousands of kernel-doc
+ comments. Please stick to the style described here.
-The opening comment mark ``/**`` is reserved for kernel-doc comments. Only
-comments so marked will be considered by the ``kernel-doc`` tool. Use it only
-for comment blocks that contain kernel-doc formatted comments. The usual ``*/``
-should be used as the closing comment marker. The lines in between should be
-prefixed by `` * `` (space star space).
-
-The function and type kernel-doc comments should be placed just before the
-function or type being described. The overview kernel-doc comments may be freely
-placed at the top indentation level.
-
-Example kernel-doc function comment::
-
- /**
- * foobar() - Brief description of foobar.
- * @argument1: Description of parameter argument1 of foobar.
- * @argument2: Description of parameter argument2 of foobar.
- *
- * Longer description of foobar.
- *
- * Return: Description of return value of foobar.
- */
- int foobar(int argument1, char *argument2)
-
-The format is similar for documentation for structures, enums, paragraphs,
-etc. See the sections below for specific details of each type.
-
-The kernel-doc structure is extracted from the comments, and proper `Sphinx C
-Domain`_ function and type descriptions with anchors are generated for them. The
-descriptions are filtered for special kernel-doc highlights and
-cross-references. See below for details.
+The kernel-doc structure is extracted from the comments, and proper
+`Sphinx C Domain`_ function and type descriptions with anchors are
+generated from them. The descriptions are filtered for special kernel-doc
+highlights and cross-references. See below for details.
.. _Sphinx C Domain: http://www.sphinx-doc.org/en/stable/domains.html
+Every function that is exported to loadable modules using
+``EXPORT_SYMBOL`` or ``EXPORT_SYMBOL_GPL`` should have a kernel-doc
+comment. Functions and data structures in header files which are intended
+to be used by modules should also have kernel-doc comments.
-Parameters and member arguments
--------------------------------
-
-The kernel-doc function comments describe each parameter to the function and
-function typedefs or each member of struct/union, in order, with the
-``@argument:`` descriptions. For each non-private member argument, one
-``@argument`` definition is needed.
-
-The ``@argument:`` descriptions begin on the very next line following
-the opening brief function description line, with no intervening blank
-comment lines.
-
-The ``@argument:`` descriptions may span multiple lines.
-
-.. note::
-
- If the ``@argument`` description has multiple lines, the continuation
- of the description should be starting exactly at the same column as
- the previous line, e. g.::
-
- * @argument: some long description
- * that continues on next lines
+It is good practice to also provide kernel-doc formatted documentation
+for functions externally visible to other kernel files (not marked
+``static``). We also recommend providing kernel-doc formatted
+documentation for private (file ``static``) routines, for consistency of
+kernel source code layout. This is lower priority and at the discretion
+of the maintainer of that kernel source file.
- or::
-
- * @argument:
- * some long description
- * that continues on next lines
-
-If a function or typedef parameter argument is ``...`` (e. g. a variable
-number of arguments), its description should be listed in kernel-doc
-notation as::
+How to format kernel-doc comments
+---------------------------------
- * @...: description
+The opening comment mark ``/**`` is used for kernel-doc comments. The
+``kernel-doc`` tool will extract comments marked this way. The rest of
+the comment is formatted like a normal multi-line comment with a column
+of asterisks on the left side, closing with ``*/`` on a line by itself.
-Private members
-~~~~~~~~~~~~~~~
+The function and type kernel-doc comments should be placed just before
+the function or type being described in order to maximise the chance
+that somebody changing the code will also change the documentation. The
+overview kernel-doc comments may be placed anywhere at the top indentation
+level.
-Inside a struct or union description, you can use the ``private:`` and
-``public:`` comment tags. Structure fields that are inside a ``private:``
-area are not listed in the generated output documentation.
+Running the ``kernel-doc`` tool with increased verbosity and without actual
+output generation may be used to verify proper formatting of the
+documentation comments. For example::
-The ``private:`` and ``public:`` tags must begin immediately following a
-``/*`` comment marker. They may optionally include comments between the
-``:`` and the ending ``*/`` marker.
+ scripts/kernel-doc -v -none drivers/foo/bar.c
-Example::
+The documentation format is verified by the kernel build when it is
+requested to perform extra gcc checks::
- /**
- * struct my_struct - short description
- * @a: first member
- * @b: second member
- * @d: fourth member
- *
- * Longer description
- */
- struct my_struct {
- int a;
- int b;
- /* private: internal use only */
- int c;
- /* public: the next one is public */
- int d;
- };
+ make W=n
Function documentation
----------------------
*
* The longer description may have multiple paragraphs.
*
+ * Context: Describes whether the function can sleep, what locks it takes,
+ * releases, or expects to be held. It can extend over multiple
+ * lines.
* Return: Describe the return value of foobar.
*
* The return value description can also have multiple paragraphs, and should
ends with an argument description, a blank comment line, or the end of the
comment block.
+Function parameters
+~~~~~~~~~~~~~~~~~~~
+
+Each function argument should be described in order, immediately following
+the short function description. Do not leave a blank line between the
+function description and the arguments, nor between the arguments.
+
+Each ``@argument:`` description may span multiple lines.
+
+.. note::
+
+ If the ``@argument`` description has multiple lines, the continuation
+ of the description should start at the same column as the previous line::
+
+ * @argument: some long description
+ * that continues on next lines
+
+ or::
+
+ * @argument:
+ * some long description
+ * that continues on next lines
+
+If a function has a variable number of arguments, its description should
+be written in kernel-doc notation as::
+
+ * @...: description
+
+Function context
+~~~~~~~~~~~~~~~~
+
+The context in which a function can be called should be described in a
+section named ``Context``. This should include whether the function
+sleeps or can be called from interrupt context, as well as what locks
+it takes, releases and expects to be held by its caller.
+
+Examples::
+
+ * Context: Any context.
+ * Context: Any context. Takes and releases the RCU lock.
+ * Context: Any context. Expects <lock> to be held by caller.
+ * Context: Process context. May sleep if @gfp flags permit.
+ * Context: Process context. Takes and releases <mutex>.
+ * Context: Softirq or process context. Takes and releases <lock>, BH-safe.
+ * Context: Interrupt context.
+
Return values
~~~~~~~~~~~~~
#) If the descriptive text you provide has lines that begin with
some phrase followed by a colon, each of those phrases will be taken
- as a new section heading, with probably won't produce the desired
+ as a new section heading, which probably won't produce the desired
effect.
Structure, union, and enumeration documentation
/**
* struct struct_name - Brief description.
- * @argument: Description of member member_name.
+ * @member1: Description of member1.
+ * @member2: Description of member2.
+ * One can provide multiple line descriptions
+ * for members.
*
* Description of the structure.
*/
-On the above, ``struct`` is used to mean structs. You can also use ``union``
-and ``enum`` to describe unions and enums. ``argument`` is used
-to mean struct and union member names as well as enumerations in an enum.
+You can replace the ``struct`` in the above example with ``union`` or
+``enum`` to describe unions or enums. ``member`` is used to mean struct
+and union member names as well as enumerations in an enum.
-The brief description following the structure name may span multiple lines, and
-ends with a member description, a blank comment line, or the end of the
-comment block.
+The brief description following the structure name may span multiple
+lines, and ends with a member description, a blank comment line, or the
+end of the comment block.
+
+Members
+~~~~~~~
-The kernel-doc data structure comments describe each member of the structure,
-in order, with the member descriptions.
+Members of structs, unions and enums should be documented the same way
+as function parameters; they immediately succeed the short description
+and may be multi-line.
+
+Inside a struct or union description, you can use the ``private:`` and
+``public:`` comment tags. Structure fields that are inside a ``private:``
+area are not listed in the generated output documentation.
+
+The ``private:`` and ``public:`` tags must begin immediately following a
+``/*`` comment marker. They may optionally include comments between the
+``:`` and the ending ``*/`` marker.
+
+Example::
+
+ /**
+ * struct my_struct - short description
+ * @a: first member
+ * @b: second member
+ * @d: fourth member
+ *
+ * Longer description
+ */
+ struct my_struct {
+ int a;
+ int b;
+ /* private: internal use only */
+ int c;
+ /* public: the next one is public */
+ int d;
+ };
Nested structs/unions
~~~~~~~~~~~~~~~~~~~~~
-It is possible to document nested structs unions, like::
+It is possible to document nested structs and unions, like::
/**
* struct nested_foobar - a struct with nested unions and structs
- * @arg1: - first argument of anonymous union/anonymous struct
- * @arg2: - second argument of anonymous union/anonymous struct
- * @arg3: - third argument of anonymous union/anonymous struct
- * @arg4: - fourth argument of anonymous union/anonymous struct
- * @bar.st1.arg1 - first argument of struct st1 on union bar
- * @bar.st1.arg2 - second argument of struct st1 on union bar
- * @bar.st2.arg1 - first argument of struct st2 on union bar
- * @bar.st2.arg2 - second argument of struct st2 on union bar
+ * @memb1: first member of anonymous union/anonymous struct
+ * @memb2: second member of anonymous union/anonymous struct
+ * @memb3: third member of anonymous union/anonymous struct
+ * @memb4: fourth member of anonymous union/anonymous struct
+ * @bar: non-anonymous union
+ * @bar.st1: struct st1 inside @bar
+ * @bar.st2: struct st2 inside @bar
+ * @bar.st1.memb1: first member of struct st1 on union bar
+ * @bar.st1.memb2: second member of struct st1 on union bar
+ * @bar.st2.memb1: first member of struct st2 on union bar
+ * @bar.st2.memb2: second member of struct st2 on union bar
+ */
struct nested_foobar {
/* Anonymous union/struct*/
union {
struct {
- int arg1;
- int arg2;
- }
+ int memb1;
+ int memb2;
+ }
struct {
- void *arg3;
- int arg4;
- }
- }
- union {
+ void *memb3;
+ int memb4;
+ }
+ }
+ union {
struct {
- int arg1;
- int arg2;
- } st1;
+ int memb1;
+ int memb2;
+ } st1;
struct {
- void *arg1;
- int arg2;
- } st2;
- } bar;
+ void *memb1;
+ int memb2;
+ } st2;
+ } bar;
};
.. note::
#) When documenting nested structs or unions, if the struct/union ``foo``
- is named, the argument ``bar`` inside it should be documented as
+ is named, the member ``bar`` inside it should be documented as
``@foo.bar:``
- #) When the nested struct/union is anonymous, the argument ``bar`` on it
+ #) When the nested struct/union is anonymous, the member ``bar`` in it
should be documented as ``@bar:``
+In-line member documentation comments
+~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
+
+The structure members may also be documented in-line within the definition.
+There are two styles, single-line comments where both the opening ``/**`` and
+closing ``*/`` are on the same line, and multi-line comments where they are each
+on a line of their own, like all other kernel-doc comments::
+
+ /**
+ * struct foo - Brief description.
+ * @foo: The Foo member.
+ */
+ struct foo {
+ int foo;
+ /**
+ * @bar: The Bar member.
+ */
+ int bar;
+ /**
+ * @baz: The Baz member.
+ *
+ * Here, the member description may contain several paragraphs.
+ */
+ int baz;
+ union {
+ /** @foobar: Single line description. */
+ int foobar;
+ };
+ /** @bar2: Description for struct @bar2 inside @foo */
+ struct {
+ /**
+ * @bar2.barbar: Description for @barbar inside @foo.bar2
+ */
+ int barbar;
+ } bar2;
+ };
+
Typedef documentation
---------------------
* @arg2: description of arg2
*
* Description of the type.
+ *
+ * Context: Locking context.
+ * Return: Meaning of the return value.
*/
typedef void (*type_name)(struct v4l2_ctrl *arg1, void *arg2);
-
Highlights and cross-references
-------------------------------
For further details, please refer to the `Sphinx C Domain`_ documentation.
-
-
-In-line member documentation comments
-~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
-
-The structure members may also be documented in-line within the definition.
-There are two styles, single-line comments where both the opening ``/**`` and
-closing ``*/`` are on the same line, and multi-line comments where they are each
-on a line of their own, like all other kernel-doc comments::
-
- /**
- * struct foo - Brief description.
- * @foo: The Foo member.
- */
- struct foo {
- int foo;
- /**
- * @bar: The Bar member.
- */
- int bar;
- /**
- * @baz: The Baz member.
- *
- * Here, the member description may contain several paragraphs.
- */
- int baz;
- /** @foobar: Single line description. */
- int foobar;
- }
-
-
Overview documentation comments
-------------------------------
as an identifier for extracting the documentation comment. Thus, the title must
be unique within the file.
-Recommendations
----------------
+Including kernel-doc comments
+=============================
-We definitely need kernel-doc formatted documentation for functions that are
-exported to loadable modules using ``EXPORT_SYMBOL`` or ``EXPORT_SYMBOL_GPL``.
+The documentation comments may be included in any of the reStructuredText
+documents using a dedicated kernel-doc Sphinx directive extension.
-We also look to provide kernel-doc formatted documentation for functions
-externally visible to other kernel files (not marked "static").
+The kernel-doc directive is of the format::
-We also recommend providing kernel-doc formatted documentation for private (file
-"static") routines, for consistency of kernel source code layout. But this is
-lower priority and at the discretion of the MAINTAINER of that kernel source
-file.
+ .. kernel-doc:: source
+ :option:
-Data structures visible in kernel include files should also be documented using
-kernel-doc formatted comments.
+The *source* is the path to a source file, relative to the kernel source
+tree. The following directive options are supported:
-How to use kernel-doc to generate man pages
--------------------------------------------
+export: *[source-pattern ...]*
+ Include documentation for all functions in *source* that have been exported
+ using ``EXPORT_SYMBOL`` or ``EXPORT_SYMBOL_GPL`` either in *source* or in any
+ of the files specified by *source-pattern*.
-If you just want to use kernel-doc to generate man pages you can do this
-from the Kernel git tree::
+ The *source-pattern* is useful when the kernel-doc comments have been placed
+ in header files, while ``EXPORT_SYMBOL`` and ``EXPORT_SYMBOL_GPL`` are next to
+ the function definitions.
+
+ Examples::
+
+ .. kernel-doc:: lib/bitmap.c
+ :export:
+
+ .. kernel-doc:: include/net/mac80211.h
+ :export: net/mac80211/*.c
+
+internal: *[source-pattern ...]*
+ Include documentation for all functions and types in *source* that have
+ **not** been exported using ``EXPORT_SYMBOL`` or ``EXPORT_SYMBOL_GPL`` either
+ in *source* or in any of the files specified by *source-pattern*.
- $ scripts/kernel-doc -man $(git grep -l '/\*\*' |grep -v Documentation/) | ./split-man.pl /tmp/man
+ Example::
-Using the small ``split-man.pl`` script below::
+ .. kernel-doc:: drivers/gpu/drm/i915/intel_audio.c
+ :internal:
+doc: *title*
+ Include documentation for the ``DOC:`` paragraph identified by *title* in
+ *source*. Spaces are allowed in *title*; do not quote the *title*. The *title*
+ is only used as an identifier for the paragraph, and is not included in the
+ output. Please make sure to have an appropriate heading in the enclosing
+ reStructuredText document.
- #!/usr/bin/perl
+ Example::
- if ($#ARGV < 0) {
- die "where do I put the results?\n";
- }
+ .. kernel-doc:: drivers/gpu/drm/i915/intel_audio.c
+ :doc: High Definition Audio over HDMI and Display Port
- mkdir $ARGV[0],0777;
- $state = 0;
- while (<STDIN>) {
- if (/^\.TH \"[^\"]*\" 9 \"([^\"]*)\"/) {
- if ($state == 1) { close OUT }
- $state = 1;
- $fn = "$ARGV[0]/$1.9";
- print STDERR "Creating $fn\n";
- open OUT, ">$fn" or die "can't open $fn: $!\n";
- print OUT $_;
- } elsif ($state != 0) {
- print OUT $_;
- }
- }
+functions: *function* *[...]*
+ Include documentation for each *function* in *source*.
+
+ Example::
+
+ .. kernel-doc:: lib/bitmap.c
+ :functions: bitmap_parselist bitmap_parselist_user
+
+Without options, the kernel-doc directive includes all documentation comments
+from the source file.
+
+The kernel-doc extension is included in the kernel source tree, at
+``Documentation/sphinx/kerneldoc.py``. Internally, it uses the
+``scripts/kernel-doc`` script to extract the documentation comments from the
+source.
+
+.. _kernel_doc:
+
+How to use kernel-doc to generate man pages
+-------------------------------------------
+
+If you just want to use kernel-doc to generate man pages you can do this
+from the kernel git tree::
- close OUT;
+ $ scripts/kernel-doc -man $(git grep -l '/\*\*' -- :^Documentation :^tools) | scripts/split-man.pl /tmp/man
This small document introduces how to test DMA drivers using dmatest module.
+.. note::
+ The test suite works only on the channels that have at least one
+ capability of the following: DMA_MEMCPY (memory-to-memory), DMA_MEMSET
+ (const-to-memory or memory-to-memory, when emulated), DMA_XOR, DMA_PQ.
+
Part 1 - How to build the test module
=====================================
The menuconfig contains an option that could be found by following path:
+
Device Drivers -> DMA Engine support -> DMA Test client
In the configuration file the option called CONFIG_DMATEST. The dmatest could
Part 2 - When dmatest is built as a module
==========================================
-Example of usage: ::
+Example of usage::
% modprobe dmatest channel=dma0chan0 timeout=2000 iterations=1 run=1
-...or: ::
+...or::
% modprobe dmatest
% echo dma0chan0 > /sys/module/dmatest/parameters/channel
% echo 1 > /sys/module/dmatest/parameters/iterations
% echo 1 > /sys/module/dmatest/parameters/run
-...or on the kernel command line: ::
+...or on the kernel command line::
dmatest.channel=dma0chan0 dmatest.timeout=2000 dmatest.iterations=1 dmatest.run=1
-..hint:: available channel list could be extracted by running the following
- command:
-
-::
+.. hint::
+ available channel list could be extracted by running the following command::
% ls -1 /sys/class/dma/
to complete before exiting. Note that if 'iterations' is set to 'infinite' then
waiting is disabled.
-Example: ::
+Example::
% modprobe dmatest run=1 iterations=42 wait=1
% modprobe -r dmatest
-...or: ::
+...or::
% modprobe dmatest run=1 iterations=42
% cat /sys/module/dmatest/parameters/wait
The module parameters that is supplied to the kernel command line will be used
for the first performed test. After user gets a control, the test could be
re-run with the same or different parameters. For the details see the above
-section "Part 2 - When dmatest is built as a module..."
+section `Part 2 - When dmatest is built as a module`_.
In both cases the module parameters are used as the actual values for the test
case. You always could check them at run-time by running ::
Part 4 - Gathering the test results
===================================
-Test results are printed to the kernel log buffer with the format: ::
+Test results are printed to the kernel log buffer with the format::
"dmatest: result <channel>: <test id>: '<error msg>' with src_off=<val> dst_off=<val> len=<val> (<err code>)"
-Example of output: ::
-
+Example of output::
% dmesg | tail -n 1
dmatest: result dma0chan0-copy0: #1: No errors with src_off=0x7bf dst_off=0x8ad len=0x3fea (0)
-The message format is unified across the different types of errors. A number in
-the parens represents additional information, e.g. error code, error counter,
-or status. A test thread also emits a summary line at completion listing the
-number of tests executed, number that failed, and a result code.
+The message format is unified across the different types of errors. A
+number in the parentheses represents additional information, e.g. error
+code, error counter, or status. A test thread also emits a summary line at
+completion listing the number of tests executed, number that failed, and a
+result code.
-Example: ::
+Example::
% dmesg | tail -n 1
dmatest: dma0chan0-copy0: summary 1 test, 0 failures 1000 iops 100000 KB/s (0)
steps to boot the device so that it's functional after the bus has been reset.
Driver and Controller APIs:
---------------------------
+---------------------------
.. kernel-doc:: include/linux/slimbus.h
:internal:
Btrees (directories, extents, free space) to aid both performance
and scalability.
-Refer to the documentation at http://oss.sgi.com/projects/xfs/
+Refer to the documentation at https://xfs.wiki.kernel.org/
for further details. This implementation is on-disk compatible
with the IRIX version of XFS.
dev-tools/index
doc-guide/index
kernel-hacking/index
+ trace/index
maintainer/index
Kernel API documentation
SYSFS FILES
- For each InfiniBand device, the InfiniBand drivers create the
- following files under /sys/class/infiniband/<device name>:
-
- node_type - Node type (CA, switch or router)
- node_guid - Node GUID
- sys_image_guid - System image GUID
-
- In addition, there is a "ports" subdirectory, with one subdirectory
- for each port. For example, if mthca0 is a 2-port HCA, there will
- be two directories:
-
- /sys/class/infiniband/mthca0/ports/1
- /sys/class/infiniband/mthca0/ports/2
-
- (A switch will only have a single "0" subdirectory for switch port
- 0; no subdirectory is created for normal switch ports)
-
- In each port subdirectory, the following files are created:
-
- cap_mask - Port capability mask
- lid - Port LID
- lid_mask_count - Port LID mask count
- rate - Port data rate (active width * active speed)
- sm_lid - Subnet manager LID for port's subnet
- sm_sl - Subnet manager SL for port's subnet
- state - Port state (DOWN, INIT, ARMED, ACTIVE or ACTIVE_DEFER)
- phys_state - Port physical state (Sleep, Polling, LinkUp, etc)
-
- There is also a "counters" subdirectory, with files
-
- VL15_dropped
- excessive_buffer_overrun_errors
- link_downed
- link_error_recovery
- local_link_integrity_errors
- port_rcv_constraint_errors
- port_rcv_data
- port_rcv_errors
- port_rcv_packets
- port_rcv_remote_physical_errors
- port_rcv_switch_relay_errors
- port_xmit_constraint_errors
- port_xmit_data
- port_xmit_discards
- port_xmit_packets
- symbol_error
-
- Each of these files contains the corresponding value from the port's
- Performance Management PortCounters attribute, as described in
- section 16.1.3.5 of the InfiniBand Architecture Specification.
-
- The "pkeys" and "gids" subdirectories contain one file for each
- entry in the port's P_Key or GID table respectively. For example,
- ports/1/pkeys/10 contains the value at index 10 in port 1's P_Key
- table.
-
- There is an optional "hw_counters" subdirectory that may be under either
- the parent device or the port subdirectories or both. If present,
- there are a list of counters provided by the hardware. They may match
- some of the counters in the counters directory, but they often include
- many other counters. In addition to the various counters, there will
- be a file named "lifespan" that configures how frequently the core
- should update the counters when they are being accessed (counters are
- not updated if they are not being accessed). The lifespan is in milli-
- seconds and defaults to 10 unless set to something else by the driver.
- Users may echo a value between 0 - 10000 to the lifespan file to set
- the length of time between updates in milliseconds.
-
-MTHCA
-
- The Mellanox HCA driver also creates the files:
-
- hw_rev - Hardware revision number
- fw_ver - Firmware version
- hca_type - HCA type: "MT23108", "MT25208 (MT23108 compat mode)",
- or "MT25208"
-
-HFI1
-
- The hfi1 driver also creates these additional files:
-
- hw_rev - hardware revision
- board_id - manufacturing board id
- tempsense - thermal sense information
- serial - board serial number
- nfreectxts - number of free user contexts
- nctxts - number of allowed contexts (PSM2)
- chip_reset - diagnostic (root only)
- boardversion - board version
-
- sdma<N>/ - one directory per sdma engine (0 - 15)
- sdma<N>/cpu_list - read-write, list of cpus for user-process to sdma
- engine assignment.
- sdma<N>/vl - read-only, vl the sdma engine maps to.
-
- The new interface will give the user control on the affinity settings
- for the hfi1 device.
- As an example, to set an sdma engine irq affinity and thread affinity
- of a user processes to use the sdma engine, which is "near" in terms
- of NUMA configuration, or physical cpu location, the user will do:
-
- echo "3" > /proc/irq/<N>/smp_affinity_list
- echo "4-7" > /sys/devices/.../sdma3/cpu_list
- cat /sys/devices/.../sdma3/vl
- 0
- echo "8" > /proc/irq/<M>/smp_affinity_list
- echo "9-12" > /sys/devices/.../sdma4/cpu_list
- cat /sys/devices/.../sdma4/vl
- 1
-
- to make sure that when a process runs on cpus 4,5,6, or 7,
- and uses vl=0, then sdma engine 3 is selected by the driver,
- and also the interrupt of the sdma engine 3 is steered to cpu 3.
- Similarly, when a process runs on cpus 9,10,11, or 12 and sets vl=1,
- then engine 4 will be selected and the irq of the sdma engine 4 is
- steered to cpu 8.
- This assumes that in the above N is the irq number of "sdma3",
- and M is irq number of "sdma4" in the /proc/interrupts file.
-
- ports/1/
- CCMgtA/
- cc_settings_bin - CCA tables used by PSM2
- cc_table_bin
- cc_prescan - enable prescaning for faster BECN response
- sc2v/ - 32 files (0 - 31) used to translate sl->vl
- sl2sc/ - 32 files (0 - 31) used to translate sl->sc
- vl2mtu/ - 16 (0 - 15) files used to determine MTU for vl
+The sysfs interface has moved to
+Documentation/ABI/stable/sysfs-class-infiniband.
byte 0: 1 1 x7 y7 1 1 1 1
byte 1: 0 x6 x5 x4 x3 x2 x1 x0
byte 2: 0 y6 y5 y4 y3 y2 y1 y0
- byte 3: 0 1 0 0 1 0 0 0
- byte 4: 0 z4 z3 z2 z1 z0 ? ?
+ byte 3: 0 1 TP SW 1 M R L
+ byte 4: 0 z6 z5 z4 z3 z2 z1 z0
byte 5: 0 0 1 1 1 1 1 1
+TP means Tap SW status when tap processing is enabled or Press status when press
+processing is enabled. SW means scroll up when 4 buttons are available.
+
ALPS Absolute Mode - Protocol Version 4
---------------------------------------
which can be found in Documentation/process/submitting-patches.rst. Code without a
proper signoff cannot be merged into the mainline.
- - Co-Developed-by: states that the patch was also created by another developer
+ - Co-developed-by: states that the patch was also created by another developer
along with the original author. This is useful at times when multiple
people work on a single patch. Note, this person also needs to have a
Signed-off-by: line in the patch as well.
FUSE
----
-- <http://sourceforge.net/projects/fuse>
+- <https://github.com/libfuse/libfuse/releases>
mcelog
------
otherwise();
}
+Also, use braces when a loop contains more than a single simple statement:
+
+.. code-block:: c
+
+ while (condition) {
+ if (test)
+ do_something();
+ }
+
3.1) Spaces
***********
and possibly be pointed in the direction of what to go work on next, if
you do not already have an idea.
-If you already have a chunk of code that you want to put into the kernel
-tree, but need some help getting it in the proper form, the
-kernel-mentors project was created to help you out with this. It is a
-mailing list, and can be found at:
-
- https://selenic.com/mailman/listinfo/kernel-mentors
-
Before making any actual modifications to the Linux kernel code, it is
imperative to understand how the code in question works. For this
purpose, nothing is better than reading through it directly (most tricky
not many people like wasting time fixing other people's bugs.
To work in the already reported bug reports, go to https://bugzilla.kernel.org.
-If you want to be advised of the future bug reports, you can subscribe to the
-bugme-new mailing list (only new bug reports are mailed here) or to the
-bugme-janitor mailing list (every change in the bugzilla is mailed here)
-
- https://lists.linux-foundation.org/mailman/listinfo/bugme-new
-
- https://lists.linux-foundation.org/mailman/listinfo/bugme-janitors
-
Mailing lists
- Auke Kok
- Peter Korsgaard
- Jiri Kosina
+ - Aaro Koskinen
- Mariusz Kozlowski
- Greg Kroah-Hartman
- Michael Krufky
============================
The Linux Kernel is provided under the terms of the GNU General Public
-License version 2 only (GPL-2.0), as published by the Free Software
-Foundation, and provided in the COPYING file. This documentation file is
-not meant to replace the COPYING file, but provides a description of how
-each source file should be annotated to make the licensing it is governed
-under clear and unambiguous.
-
-The license in the COPYING file applies to the kernel source as a whole,
-though individual source files can have a different license which is
-required to be compatible with the GPL-2.0::
+License version 2 only (GPL-2.0), as provided in LICENSES/preferred/GPL-2.0,
+with an explicit syscall exception described in
+LICENSES/exceptions/Linux-syscall-note, as described in the COPYING file.
+
+This documentation file provides a description of how each source file
+should be annotated to make its license clear and unambiguous.
+It doesn't replace the Kernel's license.
+
+The license described in the COPYING file applies to the kernel source
+as a whole, though individual source files can have a different license
+which is required to be compatible with the GPL-2.0::
GPL-1.0+ : GNU General Public License v1.0 or later
GPL-2.0+ : GNU General Public License v2.0 or later
for example, does this frequently to pass driver-specific and line
discipline-specific structures back and forth.
-The way to use magic numbers is to declare then at the beginning of
+The way to use magic numbers is to declare them at the beginning of
the structure, like so::
struct tty_ldisc {
tree.
-12) When to use Acked-by: and Cc:
----------------------------------
+12) When to use Acked-by:, Cc:, and Co-Developed-by:
+-------------------------------------------------------
The Signed-off-by: tag indicates that the signer was involved in the
development of the patch, or that he/she was in the patch's delivery path.
patch. This tag documents that potentially interested parties
have been included in the discussion.
+A Co-Developed-by: states that the patch was also created by another developer
+along with the original author. This is useful at times when multiple people
+work on a single patch. Note, this person also needs to have a Signed-off-by:
+line in the patch as well.
+
13) Using Reported-by:, Tested-by:, Reviewed-by:, Suggested-by: and Fixes:
--------------------------------------------------------------------------
- RapidIO sysfs Files
-
-~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
-
-1. RapidIO Device Subdirectories
---------------------------------
-
-For each RapidIO device, the RapidIO subsystem creates files in an individual
-subdirectory with the following name, /sys/bus/rapidio/devices/<device_name>.
-
-The format of device_name is "nn:d:iiii", where:
-
-nn - two-digit hexadecimal ID of RapidIO network where the device resides
-d - device typr: 'e' - for endpoint or 's' - for switch
-iiii - four-digit device destID for endpoints, or switchID for switches
-
-For example, below is a list of device directories that represents a typical
-RapidIO network with one switch, one host, and two agent endpoints, as it is
-seen by the enumerating host (destID = 1):
-
-/sys/bus/rapidio/devices/00:e:0000
-/sys/bus/rapidio/devices/00:e:0002
-/sys/bus/rapidio/devices/00:s:0001
-
-NOTE: An enumerating or discovering endpoint does not create a sysfs entry for
-itself, this is why an endpoint with destID=1 is not shown in the list.
-
-2. Attributes Common for All RapidIO Devices
---------------------------------------------
-
-Each device subdirectory contains the following informational read-only files:
-
- did - returns the device identifier
- vid - returns the device vendor identifier
-device_rev - returns the device revision level
- asm_did - returns identifier for the assembly containing the device
- asm_rev - returns revision level of the assembly containing the device
- asm_vid - returns vendor identifier of the assembly containing the device
- destid - returns device destination ID assigned by the enumeration routine
- (see 4.1 for switch specific details)
- lprev - returns name of previous device (switch) on the path to the device
- that that owns this attribute
- modalias - returns the device modalias
-
-In addition to the files listed above, each device has a binary attribute file
-that allows read/write access to the device configuration registers using
-the RapidIO maintenance transactions:
-
- config - reads from and writes to the device configuration registers.
-
-This attribute is similar in behavior to the "config" attribute of PCI devices
-and provides an access to the RapidIO device registers using standard file read
-and write operations.
-
-3. RapidIO Endpoint Device Attributes
--------------------------------------
-
-Currently Linux RapidIO subsystem does not create any endpoint specific sysfs
-attributes. It is possible that RapidIO master port drivers and endpoint device
-drivers will add their device-specific sysfs attributes but such attributes are
-outside the scope of this document.
-
-4. RapidIO Switch Device Attributes
------------------------------------
-
-RapidIO switches have additional attributes in sysfs. RapidIO subsystem supports
-common and device-specific sysfs attributes for switches. Because switches are
-integrated into the RapidIO subsystem, it offers a method to create
-device-specific sysfs attributes by specifying a callback function that may be
-set by the switch initialization routine during enumeration or discovery process.
-
-4.1 Common Switch Attributes
-
- routes - reports switch routing information in "destID port" format. This
- attribute reports only valid routing table entries, one line for
- each entry.
- destid - device destination ID that defines a route to the switch
- hopcount - number of hops on the path to the switch
- lnext - returns names of devices linked to the switch except one of a device
- linked to the ingress port (reported as "lprev"). This is an array
- names with number of lines equal to number of ports in switch. If
- a switch port has no attached device, returns "null" instead of
- a device name.
-
-4.2 Device-specific Switch Attributes
-
-Device-specific switch attributes are listed for each RapidIO switch driver
-that exports additional attributes.
-
-IDT_GEN2:
- errlog - reads contents of device error log until it is empty.
-
-
-5. RapidIO Bus Attributes
--------------------------
-
-RapidIO bus subdirectory /sys/bus/rapidio implements the following bus-specific
-attribute:
-
- scan - allows to trigger enumeration discovery process from user space. This
- is a write-only attribute. To initiate an enumeration or discovery
- process on specific mport device, a user needs to write mport_ID (not
- RapidIO destination ID) into this file. The mport_ID is a sequential
- number (0 ... RIO_MAX_MPORTS) assigned to the mport device.
- For example, for a machine with a single RapidIO controller, mport_ID
- for that controller always will be 0.
- To initiate RapidIO enumeration/discovery on all available mports
- a user must write '-1' (or RIO_MPORT_ANY) into this attribute file.
-
-
-6. RapidIO Bus Controllers/Ports
---------------------------------
-
-On-chip RapidIO controllers and PCIe-to-RapidIO bridges (referenced as
-"Master Port" or "mport") are presented in sysfs as the special class of
-devices: "rapidio_port".
-
-The /sys/class/rapidio_port subdirectory contains individual subdirectories
-named as "rapidioN" where N = mport ID registered with RapidIO subsystem.
-
-NOTE: An mport ID is not a RapidIO destination ID assigned to a given local
-mport device.
-
-Each mport device subdirectory in addition to standard entries contains the
-following device-specific attributes:
-
- port_destid - reports RapidIO destination ID assigned to the given RapidIO
- mport device. If value 0xFFFFFFFF is returned this means that
- no valid destination ID have been assigned to the mport (yet).
- Normally, before enumeration/discovery have been executed only
- fabric enumerating mports have a valid destination ID assigned
- to them using "hdid=..." rapidio module parameter.
- sys_size - reports RapidIO common transport system size:
- 0 = small (8-bit destination ID, max. 256 devices),
- 1 = large (16-bit destination ID, max. 65536 devices).
-
-After enumeration or discovery was performed for a given mport device,
-the corresponding subdirectory will also contain subdirectories for each
-child RapidIO device connected to the mport. Naming conventions for RapidIO
-devices are described in Section 1 above.
-
-The example below shows mport device subdirectory with several child RapidIO
-devices attached to it.
-
-[rio@rapidio ~]$ ls /sys/class/rapidio_port/rapidio0/ -l
-total 0
-drwxr-xr-x 3 root root 0 Feb 11 15:10 00:e:0001
-drwxr-xr-x 3 root root 0 Feb 11 15:10 00:e:0004
-drwxr-xr-x 3 root root 0 Feb 11 15:10 00:e:0007
-drwxr-xr-x 3 root root 0 Feb 11 15:10 00:s:0002
-drwxr-xr-x 3 root root 0 Feb 11 15:10 00:s:0003
-drwxr-xr-x 3 root root 0 Feb 11 15:10 00:s:0005
-lrwxrwxrwx 1 root root 0 Feb 11 15:11 device -> ../../../0000:01:00.0
--r--r--r-- 1 root root 4096 Feb 11 15:11 port_destid
-drwxr-xr-x 2 root root 0 Feb 11 15:11 power
-lrwxrwxrwx 1 root root 0 Feb 11 15:04 subsystem -> ../../../../../../class/rapidio_port
--r--r--r-- 1 root root 4096 Feb 11 15:11 sys_size
--rw-r--r-- 1 root root 4096 Feb 11 15:04 uevent
+The RapidIO sysfs files have moved to:
+Documentation/ABI/testing/sysfs-bus-rapidio and
+Documentation/ABI/testing/sysfs-class-rapidio
--- /dev/null
+============================
+Subsystem Trace Points: kmem
+============================
+
+The kmem tracing system captures events related to object and page allocation
+within the kernel. Broadly speaking there are five major subheadings.
+
+ - Slab allocation of small objects of unknown type (kmalloc)
+ - Slab allocation of small objects of known type
+ - Page allocation
+ - Per-CPU Allocator Activity
+ - External Fragmentation
+
+This document describes what each of the tracepoints is and why they
+might be useful.
+
+1. Slab allocation of small objects of unknown type
+===================================================
+::
+
+ kmalloc call_site=%lx ptr=%p bytes_req=%zu bytes_alloc=%zu gfp_flags=%s
+ kmalloc_node call_site=%lx ptr=%p bytes_req=%zu bytes_alloc=%zu gfp_flags=%s node=%d
+ kfree call_site=%lx ptr=%p
+
+Heavy activity for these events may indicate that a specific cache is
+justified, particularly if kmalloc slab pages are getting significantly
+internal fragmented as a result of the allocation pattern. By correlating
+kmalloc with kfree, it may be possible to identify memory leaks and where
+the allocation sites were.
+
+
+2. Slab allocation of small objects of known type
+=================================================
+::
+
+ kmem_cache_alloc call_site=%lx ptr=%p bytes_req=%zu bytes_alloc=%zu gfp_flags=%s
+ kmem_cache_alloc_node call_site=%lx ptr=%p bytes_req=%zu bytes_alloc=%zu gfp_flags=%s node=%d
+ kmem_cache_free call_site=%lx ptr=%p
+
+These events are similar in usage to the kmalloc-related events except that
+it is likely easier to pin the event down to a specific cache. At the time
+of writing, no information is available on what slab is being allocated from,
+but the call_site can usually be used to extrapolate that information.
+
+3. Page allocation
+==================
+::
+
+ mm_page_alloc page=%p pfn=%lu order=%d migratetype=%d gfp_flags=%s
+ mm_page_alloc_zone_locked page=%p pfn=%lu order=%u migratetype=%d cpu=%d percpu_refill=%d
+ mm_page_free page=%p pfn=%lu order=%d
+ mm_page_free_batched page=%p pfn=%lu order=%d cold=%d
+
+These four events deal with page allocation and freeing. mm_page_alloc is
+a simple indicator of page allocator activity. Pages may be allocated from
+the per-CPU allocator (high performance) or the buddy allocator.
+
+If pages are allocated directly from the buddy allocator, the
+mm_page_alloc_zone_locked event is triggered. This event is important as high
+amounts of activity imply high activity on the zone->lock. Taking this lock
+impairs performance by disabling interrupts, dirtying cache lines between
+CPUs and serialising many CPUs.
+
+When a page is freed directly by the caller, the only mm_page_free event
+is triggered. Significant amounts of activity here could indicate that the
+callers should be batching their activities.
+
+When pages are freed in batch, the also mm_page_free_batched is triggered.
+Broadly speaking, pages are taken off the LRU lock in bulk and
+freed in batch with a page list. Significant amounts of activity here could
+indicate that the system is under memory pressure and can also indicate
+contention on the zone->lru_lock.
+
+4. Per-CPU Allocator Activity
+=============================
+::
+
+ mm_page_alloc_zone_locked page=%p pfn=%lu order=%u migratetype=%d cpu=%d percpu_refill=%d
+ mm_page_pcpu_drain page=%p pfn=%lu order=%d cpu=%d migratetype=%d
+
+In front of the page allocator is a per-cpu page allocator. It exists only
+for order-0 pages, reduces contention on the zone->lock and reduces the
+amount of writing on struct page.
+
+When a per-CPU list is empty or pages of the wrong type are allocated,
+the zone->lock will be taken once and the per-CPU list refilled. The event
+triggered is mm_page_alloc_zone_locked for each page allocated with the
+event indicating whether it is for a percpu_refill or not.
+
+When the per-CPU list is too full, a number of pages are freed, each one
+which triggers a mm_page_pcpu_drain event.
+
+The individual nature of the events is so that pages can be tracked
+between allocation and freeing. A number of drain or refill pages that occur
+consecutively imply the zone->lock being taken once. Large amounts of per-CPU
+refills and drains could imply an imbalance between CPUs where too much work
+is being concentrated in one place. It could also indicate that the per-CPU
+lists should be a larger size. Finally, large amounts of refills on one CPU
+and drains on another could be a factor in causing large amounts of cache
+line bounces due to writes between CPUs and worth investigating if pages
+can be allocated and freed on the same CPU through some algorithm change.
+
+5. External Fragmentation
+=========================
+::
+
+ mm_page_alloc_extfrag page=%p pfn=%lu alloc_order=%d fallback_order=%d pageblock_order=%d alloc_migratetype=%d fallback_migratetype=%d fragmenting=%d change_ownership=%d
+
+External fragmentation affects whether a high-order allocation will be
+successful or not. For some types of hardware, this is important although
+it is avoided where possible. If the system is using huge pages and needs
+to be able to resize the pool over the lifetime of the system, this value
+is important.
+
+Large numbers of this event implies that memory is fragmenting and
+high-order allocations will start failing at some time in the future. One
+means of reducing the occurrence of this event is to increase the size of
+min_free_kbytes in increments of 3*pageblock_size*nr_online_nodes where
+pageblock_size is usually the size of the default hugepage size.
+++ /dev/null
- Subsystem Trace Points: kmem
-
-The kmem tracing system captures events related to object and page allocation
-within the kernel. Broadly speaking there are five major subheadings.
-
- o Slab allocation of small objects of unknown type (kmalloc)
- o Slab allocation of small objects of known type
- o Page allocation
- o Per-CPU Allocator Activity
- o External Fragmentation
-
-This document describes what each of the tracepoints is and why they
-might be useful.
-
-1. Slab allocation of small objects of unknown type
-===================================================
-kmalloc call_site=%lx ptr=%p bytes_req=%zu bytes_alloc=%zu gfp_flags=%s
-kmalloc_node call_site=%lx ptr=%p bytes_req=%zu bytes_alloc=%zu gfp_flags=%s node=%d
-kfree call_site=%lx ptr=%p
-
-Heavy activity for these events may indicate that a specific cache is
-justified, particularly if kmalloc slab pages are getting significantly
-internal fragmented as a result of the allocation pattern. By correlating
-kmalloc with kfree, it may be possible to identify memory leaks and where
-the allocation sites were.
-
-
-2. Slab allocation of small objects of known type
-=================================================
-kmem_cache_alloc call_site=%lx ptr=%p bytes_req=%zu bytes_alloc=%zu gfp_flags=%s
-kmem_cache_alloc_node call_site=%lx ptr=%p bytes_req=%zu bytes_alloc=%zu gfp_flags=%s node=%d
-kmem_cache_free call_site=%lx ptr=%p
-
-These events are similar in usage to the kmalloc-related events except that
-it is likely easier to pin the event down to a specific cache. At the time
-of writing, no information is available on what slab is being allocated from,
-but the call_site can usually be used to extrapolate that information.
-
-3. Page allocation
-==================
-mm_page_alloc page=%p pfn=%lu order=%d migratetype=%d gfp_flags=%s
-mm_page_alloc_zone_locked page=%p pfn=%lu order=%u migratetype=%d cpu=%d percpu_refill=%d
-mm_page_free page=%p pfn=%lu order=%d
-mm_page_free_batched page=%p pfn=%lu order=%d cold=%d
-
-These four events deal with page allocation and freeing. mm_page_alloc is
-a simple indicator of page allocator activity. Pages may be allocated from
-the per-CPU allocator (high performance) or the buddy allocator.
-
-If pages are allocated directly from the buddy allocator, the
-mm_page_alloc_zone_locked event is triggered. This event is important as high
-amounts of activity imply high activity on the zone->lock. Taking this lock
-impairs performance by disabling interrupts, dirtying cache lines between
-CPUs and serialising many CPUs.
-
-When a page is freed directly by the caller, the only mm_page_free event
-is triggered. Significant amounts of activity here could indicate that the
-callers should be batching their activities.
-
-When pages are freed in batch, the also mm_page_free_batched is triggered.
-Broadly speaking, pages are taken off the LRU lock in bulk and
-freed in batch with a page list. Significant amounts of activity here could
-indicate that the system is under memory pressure and can also indicate
-contention on the zone->lru_lock.
-
-4. Per-CPU Allocator Activity
-=============================
-mm_page_alloc_zone_locked page=%p pfn=%lu order=%u migratetype=%d cpu=%d percpu_refill=%d
-mm_page_pcpu_drain page=%p pfn=%lu order=%d cpu=%d migratetype=%d
-
-In front of the page allocator is a per-cpu page allocator. It exists only
-for order-0 pages, reduces contention on the zone->lock and reduces the
-amount of writing on struct page.
-
-When a per-CPU list is empty or pages of the wrong type are allocated,
-the zone->lock will be taken once and the per-CPU list refilled. The event
-triggered is mm_page_alloc_zone_locked for each page allocated with the
-event indicating whether it is for a percpu_refill or not.
-
-When the per-CPU list is too full, a number of pages are freed, each one
-which triggers a mm_page_pcpu_drain event.
-
-The individual nature of the events is so that pages can be tracked
-between allocation and freeing. A number of drain or refill pages that occur
-consecutively imply the zone->lock being taken once. Large amounts of per-CPU
-refills and drains could imply an imbalance between CPUs where too much work
-is being concentrated in one place. It could also indicate that the per-CPU
-lists should be a larger size. Finally, large amounts of refills on one CPU
-and drains on another could be a factor in causing large amounts of cache
-line bounces due to writes between CPUs and worth investigating if pages
-can be allocated and freed on the same CPU through some algorithm change.
-
-5. External Fragmentation
-=========================
-mm_page_alloc_extfrag page=%p pfn=%lu alloc_order=%d fallback_order=%d pageblock_order=%d alloc_migratetype=%d fallback_migratetype=%d fragmenting=%d change_ownership=%d
-
-External fragmentation affects whether a high-order allocation will be
-successful or not. For some types of hardware, this is important although
-it is avoided where possible. If the system is using huge pages and needs
-to be able to resize the pool over the lifetime of the system, this value
-is important.
-
-Large numbers of this event implies that memory is fragmenting and
-high-order allocations will start failing at some time in the future. One
-means of reducing the occurrence of this event is to increase the size of
-min_free_kbytes in increments of 3*pageblock_size*nr_online_nodes where
-pageblock_size is usually the size of the default hugepage size.
--- /dev/null
+================
+MSR Trace Events
+================
+
+The x86 kernel supports tracing most MSR (Model Specific Register) accesses.
+To see the definition of the MSRs on Intel systems please see the SDM
+at http://www.intel.com/sdm (Volume 3)
+
+Available trace points:
+
+/sys/kernel/debug/tracing/events/msr/
+
+Trace MSR reads:
+
+read_msr
+
+ - msr: MSR number
+ - val: Value written
+ - failed: 1 if the access failed, otherwise 0
+
+
+Trace MSR writes:
+
+write_msr
+
+ - msr: MSR number
+ - val: Value written
+ - failed: 1 if the access failed, otherwise 0
+
+
+Trace RDPMC in kernel:
+
+rdpmc
+
+The trace data can be post processed with the postprocess/decode_msr.py script::
+
+ cat /sys/kernel/debug/tracing/trace | decode_msr.py /usr/src/linux/include/asm/msr-index.h
+
+to add symbolic MSR names.
+
+++ /dev/null
-
-The x86 kernel supports tracing most MSR (Model Specific Register) accesses.
-To see the definition of the MSRs on Intel systems please see the SDM
-at http://www.intel.com/sdm (Volume 3)
-
-Available trace points:
-
-/sys/kernel/debug/tracing/events/msr/
-
-Trace MSR reads
-
-read_msr
-
-msr: MSR number
-val: Value written
-failed: 1 if the access failed, otherwise 0
-
-
-Trace MSR writes
-
-write_msr
-
-msr: MSR number
-val: Value written
-failed: 1 if the access failed, otherwise 0
-
-
-Trace RDPMC in kernel
-
-rdpmc
-
-The trace data can be post processed with the postprocess/decode_msr.py script
-
-cat /sys/kernel/debug/tracing/trace | decode_msr.py /usr/src/linux/include/asm/msr-index.h
-
-to add symbolic MSR names.
-
--- /dev/null
+================
+NMI Trace Events
+================
+
+These events normally show up here:
+
+ /sys/kernel/debug/tracing/events/nmi
+
+
+nmi_handler
+-----------
+
+You might want to use this tracepoint if you suspect that your
+NMI handlers are hogging large amounts of CPU time. The kernel
+will warn if it sees long-running handlers::
+
+ INFO: NMI handler took too long to run: 9.207 msecs
+
+and this tracepoint will allow you to drill down and get some
+more details.
+
+Let's say you suspect that perf_event_nmi_handler() is causing
+you some problems and you only want to trace that handler
+specifically. You need to find its address::
+
+ $ grep perf_event_nmi_handler /proc/kallsyms
+ ffffffff81625600 t perf_event_nmi_handler
+
+Let's also say you are only interested in when that function is
+really hogging a lot of CPU time, like a millisecond at a time.
+Note that the kernel's output is in milliseconds, but the input
+to the filter is in nanoseconds! You can filter on 'delta_ns'::
+
+ cd /sys/kernel/debug/tracing/events/nmi/nmi_handler
+ echo 'handler==0xffffffff81625600 && delta_ns>1000000' > filter
+ echo 1 > enable
+
+Your output would then look like::
+
+ $ cat /sys/kernel/debug/tracing/trace_pipe
+ <idle>-0 [000] d.h3 505.397558: nmi_handler: perf_event_nmi_handler() delta_ns: 3236765 handled: 1
+ <idle>-0 [000] d.h3 505.805893: nmi_handler: perf_event_nmi_handler() delta_ns: 3174234 handled: 1
+ <idle>-0 [000] d.h3 506.158206: nmi_handler: perf_event_nmi_handler() delta_ns: 3084642 handled: 1
+ <idle>-0 [000] d.h3 506.334346: nmi_handler: perf_event_nmi_handler() delta_ns: 3080351 handled: 1
+
+++ /dev/null
-NMI Trace Events
-
-These events normally show up here:
-
- /sys/kernel/debug/tracing/events/nmi
-
---
-
-nmi_handler:
-
-You might want to use this tracepoint if you suspect that your
-NMI handlers are hogging large amounts of CPU time. The kernel
-will warn if it sees long-running handlers:
-
- INFO: NMI handler took too long to run: 9.207 msecs
-
-and this tracepoint will allow you to drill down and get some
-more details.
-
-Let's say you suspect that perf_event_nmi_handler() is causing
-you some problems and you only want to trace that handler
-specifically. You need to find its address:
-
- $ grep perf_event_nmi_handler /proc/kallsyms
- ffffffff81625600 t perf_event_nmi_handler
-
-Let's also say you are only interested in when that function is
-really hogging a lot of CPU time, like a millisecond at a time.
-Note that the kernel's output is in milliseconds, but the input
-to the filter is in nanoseconds! You can filter on 'delta_ns':
-
-cd /sys/kernel/debug/tracing/events/nmi/nmi_handler
-echo 'handler==0xffffffff81625600 && delta_ns>1000000' > filter
-echo 1 > enable
-
-Your output would then look like:
-
-$ cat /sys/kernel/debug/tracing/trace_pipe
-<idle>-0 [000] d.h3 505.397558: nmi_handler: perf_event_nmi_handler() delta_ns: 3236765 handled: 1
-<idle>-0 [000] d.h3 505.805893: nmi_handler: perf_event_nmi_handler() delta_ns: 3174234 handled: 1
-<idle>-0 [000] d.h3 506.158206: nmi_handler: perf_event_nmi_handler() delta_ns: 3084642 handled: 1
-<idle>-0 [000] d.h3 506.334346: nmi_handler: perf_event_nmi_handler() delta_ns: 3080351 handled: 1
-
--- /dev/null
+=============================
+Subsystem Trace Points: power
+=============================
+
+The power tracing system captures events related to power transitions
+within the kernel. Broadly speaking there are three major subheadings:
+
+ - Power state switch which reports events related to suspend (S-states),
+ cpuidle (C-states) and cpufreq (P-states)
+ - System clock related changes
+ - Power domains related changes and transitions
+
+This document describes what each of the tracepoints is and why they
+might be useful.
+
+Cf. include/trace/events/power.h for the events definitions.
+
+1. Power state switch events
+============================
+
+1.1 Trace API
+-----------------
+
+A 'cpu' event class gathers the CPU-related events: cpuidle and
+cpufreq.
+::
+
+ cpu_idle "state=%lu cpu_id=%lu"
+ cpu_frequency "state=%lu cpu_id=%lu"
+
+A suspend event is used to indicate the system going in and out of the
+suspend mode:
+::
+
+ machine_suspend "state=%lu"
+
+
+Note: the value of '-1' or '4294967295' for state means an exit from the current state,
+i.e. trace_cpu_idle(4, smp_processor_id()) means that the system
+enters the idle state 4, while trace_cpu_idle(PWR_EVENT_EXIT, smp_processor_id())
+means that the system exits the previous idle state.
+
+The event which has 'state=4294967295' in the trace is very important to the user
+space tools which are using it to detect the end of the current state, and so to
+correctly draw the states diagrams and to calculate accurate statistics etc.
+
+2. Clocks events
+================
+The clock events are used for clock enable/disable and for
+clock rate change.
+::
+
+ clock_enable "%s state=%lu cpu_id=%lu"
+ clock_disable "%s state=%lu cpu_id=%lu"
+ clock_set_rate "%s state=%lu cpu_id=%lu"
+
+The first parameter gives the clock name (e.g. "gpio1_iclk").
+The second parameter is '1' for enable, '0' for disable, the target
+clock rate for set_rate.
+
+3. Power domains events
+=======================
+The power domain events are used for power domains transitions
+::
+
+ power_domain_target "%s state=%lu cpu_id=%lu"
+
+The first parameter gives the power domain name (e.g. "mpu_pwrdm").
+The second parameter is the power domain target state.
+
+4. PM QoS events
+================
+The PM QoS events are used for QoS add/update/remove request and for
+target/flags update.
+::
+
+ pm_qos_add_request "pm_qos_class=%s value=%d"
+ pm_qos_update_request "pm_qos_class=%s value=%d"
+ pm_qos_remove_request "pm_qos_class=%s value=%d"
+ pm_qos_update_request_timeout "pm_qos_class=%s value=%d, timeout_us=%ld"
+
+The first parameter gives the QoS class name (e.g. "CPU_DMA_LATENCY").
+The second parameter is value to be added/updated/removed.
+The third parameter is timeout value in usec.
+::
+
+ pm_qos_update_target "action=%s prev_value=%d curr_value=%d"
+ pm_qos_update_flags "action=%s prev_value=0x%x curr_value=0x%x"
+
+The first parameter gives the QoS action name (e.g. "ADD_REQ").
+The second parameter is the previous QoS value.
+The third parameter is the current QoS value to update.
+
+And, there are also events used for device PM QoS add/update/remove request.
+::
+
+ dev_pm_qos_add_request "device=%s type=%s new_value=%d"
+ dev_pm_qos_update_request "device=%s type=%s new_value=%d"
+ dev_pm_qos_remove_request "device=%s type=%s new_value=%d"
+
+The first parameter gives the device name which tries to add/update/remove
+QoS requests.
+The second parameter gives the request type (e.g. "DEV_PM_QOS_RESUME_LATENCY").
+The third parameter is value to be added/updated/removed.
+++ /dev/null
-
- Subsystem Trace Points: power
-
-The power tracing system captures events related to power transitions
-within the kernel. Broadly speaking there are three major subheadings:
-
- o Power state switch which reports events related to suspend (S-states),
- cpuidle (C-states) and cpufreq (P-states)
- o System clock related changes
- o Power domains related changes and transitions
-
-This document describes what each of the tracepoints is and why they
-might be useful.
-
-Cf. include/trace/events/power.h for the events definitions.
-
-1. Power state switch events
-============================
-
-1.1 Trace API
------------------
-
-A 'cpu' event class gathers the CPU-related events: cpuidle and
-cpufreq.
-
-cpu_idle "state=%lu cpu_id=%lu"
-cpu_frequency "state=%lu cpu_id=%lu"
-
-A suspend event is used to indicate the system going in and out of the
-suspend mode:
-
-machine_suspend "state=%lu"
-
-
-Note: the value of '-1' or '4294967295' for state means an exit from the current state,
-i.e. trace_cpu_idle(4, smp_processor_id()) means that the system
-enters the idle state 4, while trace_cpu_idle(PWR_EVENT_EXIT, smp_processor_id())
-means that the system exits the previous idle state.
-
-The event which has 'state=4294967295' in the trace is very important to the user
-space tools which are using it to detect the end of the current state, and so to
-correctly draw the states diagrams and to calculate accurate statistics etc.
-
-2. Clocks events
-================
-The clock events are used for clock enable/disable and for
-clock rate change.
-
-clock_enable "%s state=%lu cpu_id=%lu"
-clock_disable "%s state=%lu cpu_id=%lu"
-clock_set_rate "%s state=%lu cpu_id=%lu"
-
-The first parameter gives the clock name (e.g. "gpio1_iclk").
-The second parameter is '1' for enable, '0' for disable, the target
-clock rate for set_rate.
-
-3. Power domains events
-=======================
-The power domain events are used for power domains transitions
-
-power_domain_target "%s state=%lu cpu_id=%lu"
-
-The first parameter gives the power domain name (e.g. "mpu_pwrdm").
-The second parameter is the power domain target state.
-
-4. PM QoS events
-================
-The PM QoS events are used for QoS add/update/remove request and for
-target/flags update.
-
-pm_qos_add_request "pm_qos_class=%s value=%d"
-pm_qos_update_request "pm_qos_class=%s value=%d"
-pm_qos_remove_request "pm_qos_class=%s value=%d"
-pm_qos_update_request_timeout "pm_qos_class=%s value=%d, timeout_us=%ld"
-
-The first parameter gives the QoS class name (e.g. "CPU_DMA_LATENCY").
-The second parameter is value to be added/updated/removed.
-The third parameter is timeout value in usec.
-
-pm_qos_update_target "action=%s prev_value=%d curr_value=%d"
-pm_qos_update_flags "action=%s prev_value=0x%x curr_value=0x%x"
-
-The first parameter gives the QoS action name (e.g. "ADD_REQ").
-The second parameter is the previous QoS value.
-The third parameter is the current QoS value to update.
-
-And, there are also events used for device PM QoS add/update/remove request.
-
-dev_pm_qos_add_request "device=%s type=%s new_value=%d"
-dev_pm_qos_update_request "device=%s type=%s new_value=%d"
-dev_pm_qos_remove_request "device=%s type=%s new_value=%d"
-
-The first parameter gives the device name which tries to add/update/remove
-QoS requests.
-The second parameter gives the request type (e.g. "DEV_PM_QOS_RESUME_LATENCY").
-The third parameter is value to be added/updated/removed.
--- /dev/null
+=============
+Event Tracing
+=============
+
+:Author: Theodore Ts'o
+:Updated: Li Zefan and Tom Zanussi
+
+1. Introduction
+===============
+
+Tracepoints (see Documentation/trace/tracepoints.txt) can be used
+without creating custom kernel modules to register probe functions
+using the event tracing infrastructure.
+
+Not all tracepoints can be traced using the event tracing system;
+the kernel developer must provide code snippets which define how the
+tracing information is saved into the tracing buffer, and how the
+tracing information should be printed.
+
+2. Using Event Tracing
+======================
+
+2.1 Via the 'set_event' interface
+---------------------------------
+
+The events which are available for tracing can be found in the file
+/sys/kernel/debug/tracing/available_events.
+
+To enable a particular event, such as 'sched_wakeup', simply echo it
+to /sys/kernel/debug/tracing/set_event. For example::
+
+ # echo sched_wakeup >> /sys/kernel/debug/tracing/set_event
+
+.. Note:: '>>' is necessary, otherwise it will firstly disable all the events.
+
+To disable an event, echo the event name to the set_event file prefixed
+with an exclamation point::
+
+ # echo '!sched_wakeup' >> /sys/kernel/debug/tracing/set_event
+
+To disable all events, echo an empty line to the set_event file::
+
+ # echo > /sys/kernel/debug/tracing/set_event
+
+To enable all events, echo ``*:*`` or ``*:`` to the set_event file::
+
+ # echo *:* > /sys/kernel/debug/tracing/set_event
+
+The events are organized into subsystems, such as ext4, irq, sched,
+etc., and a full event name looks like this: <subsystem>:<event>. The
+subsystem name is optional, but it is displayed in the available_events
+file. All of the events in a subsystem can be specified via the syntax
+``<subsystem>:*``; for example, to enable all irq events, you can use the
+command::
+
+ # echo 'irq:*' > /sys/kernel/debug/tracing/set_event
+
+2.2 Via the 'enable' toggle
+---------------------------
+
+The events available are also listed in /sys/kernel/debug/tracing/events/ hierarchy
+of directories.
+
+To enable event 'sched_wakeup'::
+
+ # echo 1 > /sys/kernel/debug/tracing/events/sched/sched_wakeup/enable
+
+To disable it::
+
+ # echo 0 > /sys/kernel/debug/tracing/events/sched/sched_wakeup/enable
+
+To enable all events in sched subsystem::
+
+ # echo 1 > /sys/kernel/debug/tracing/events/sched/enable
+
+To enable all events::
+
+ # echo 1 > /sys/kernel/debug/tracing/events/enable
+
+When reading one of these enable files, there are four results:
+
+ - 0 - all events this file affects are disabled
+ - 1 - all events this file affects are enabled
+ - X - there is a mixture of events enabled and disabled
+ - ? - this file does not affect any event
+
+2.3 Boot option
+---------------
+
+In order to facilitate early boot debugging, use boot option::
+
+ trace_event=[event-list]
+
+event-list is a comma separated list of events. See section 2.1 for event
+format.
+
+3. Defining an event-enabled tracepoint
+=======================================
+
+See The example provided in samples/trace_events
+
+4. Event formats
+================
+
+Each trace event has a 'format' file associated with it that contains
+a description of each field in a logged event. This information can
+be used to parse the binary trace stream, and is also the place to
+find the field names that can be used in event filters (see section 5).
+
+It also displays the format string that will be used to print the
+event in text mode, along with the event name and ID used for
+profiling.
+
+Every event has a set of ``common`` fields associated with it; these are
+the fields prefixed with ``common_``. The other fields vary between
+events and correspond to the fields defined in the TRACE_EVENT
+definition for that event.
+
+Each field in the format has the form::
+
+ field:field-type field-name; offset:N; size:N;
+
+where offset is the offset of the field in the trace record and size
+is the size of the data item, in bytes.
+
+For example, here's the information displayed for the 'sched_wakeup'
+event::
+
+ # cat /sys/kernel/debug/tracing/events/sched/sched_wakeup/format
+
+ name: sched_wakeup
+ ID: 60
+ format:
+ field:unsigned short common_type; offset:0; size:2;
+ field:unsigned char common_flags; offset:2; size:1;
+ field:unsigned char common_preempt_count; offset:3; size:1;
+ field:int common_pid; offset:4; size:4;
+ field:int common_tgid; offset:8; size:4;
+
+ field:char comm[TASK_COMM_LEN]; offset:12; size:16;
+ field:pid_t pid; offset:28; size:4;
+ field:int prio; offset:32; size:4;
+ field:int success; offset:36; size:4;
+ field:int cpu; offset:40; size:4;
+
+ print fmt: "task %s:%d [%d] success=%d [%03d]", REC->comm, REC->pid,
+ REC->prio, REC->success, REC->cpu
+
+This event contains 10 fields, the first 5 common and the remaining 5
+event-specific. All the fields for this event are numeric, except for
+'comm' which is a string, a distinction important for event filtering.
+
+5. Event filtering
+==================
+
+Trace events can be filtered in the kernel by associating boolean
+'filter expressions' with them. As soon as an event is logged into
+the trace buffer, its fields are checked against the filter expression
+associated with that event type. An event with field values that
+'match' the filter will appear in the trace output, and an event whose
+values don't match will be discarded. An event with no filter
+associated with it matches everything, and is the default when no
+filter has been set for an event.
+
+5.1 Expression syntax
+---------------------
+
+A filter expression consists of one or more 'predicates' that can be
+combined using the logical operators '&&' and '||'. A predicate is
+simply a clause that compares the value of a field contained within a
+logged event with a constant value and returns either 0 or 1 depending
+on whether the field value matched (1) or didn't match (0)::
+
+ field-name relational-operator value
+
+Parentheses can be used to provide arbitrary logical groupings and
+double-quotes can be used to prevent the shell from interpreting
+operators as shell metacharacters.
+
+The field-names available for use in filters can be found in the
+'format' files for trace events (see section 4).
+
+The relational-operators depend on the type of the field being tested:
+
+The operators available for numeric fields are:
+
+==, !=, <, <=, >, >=, &
+
+And for string fields they are:
+
+==, !=, ~
+
+The glob (~) accepts a wild card character (\*,?) and character classes
+([). For example::
+
+ prev_comm ~ "*sh"
+ prev_comm ~ "sh*"
+ prev_comm ~ "*sh*"
+ prev_comm ~ "ba*sh"
+
+5.2 Setting filters
+-------------------
+
+A filter for an individual event is set by writing a filter expression
+to the 'filter' file for the given event.
+
+For example::
+
+ # cd /sys/kernel/debug/tracing/events/sched/sched_wakeup
+ # echo "common_preempt_count > 4" > filter
+
+A slightly more involved example::
+
+ # cd /sys/kernel/debug/tracing/events/signal/signal_generate
+ # echo "((sig >= 10 && sig < 15) || sig == 17) && comm != bash" > filter
+
+If there is an error in the expression, you'll get an 'Invalid
+argument' error when setting it, and the erroneous string along with
+an error message can be seen by looking at the filter e.g.::
+
+ # cd /sys/kernel/debug/tracing/events/signal/signal_generate
+ # echo "((sig >= 10 && sig < 15) || dsig == 17) && comm != bash" > filter
+ -bash: echo: write error: Invalid argument
+ # cat filter
+ ((sig >= 10 && sig < 15) || dsig == 17) && comm != bash
+ ^
+ parse_error: Field not found
+
+Currently the caret ('^') for an error always appears at the beginning of
+the filter string; the error message should still be useful though
+even without more accurate position info.
+
+5.3 Clearing filters
+--------------------
+
+To clear the filter for an event, write a '0' to the event's filter
+file.
+
+To clear the filters for all events in a subsystem, write a '0' to the
+subsystem's filter file.
+
+5.3 Subsystem filters
+---------------------
+
+For convenience, filters for every event in a subsystem can be set or
+cleared as a group by writing a filter expression into the filter file
+at the root of the subsystem. Note however, that if a filter for any
+event within the subsystem lacks a field specified in the subsystem
+filter, or if the filter can't be applied for any other reason, the
+filter for that event will retain its previous setting. This can
+result in an unintended mixture of filters which could lead to
+confusing (to the user who might think different filters are in
+effect) trace output. Only filters that reference just the common
+fields can be guaranteed to propagate successfully to all events.
+
+Here are a few subsystem filter examples that also illustrate the
+above points:
+
+Clear the filters on all events in the sched subsystem::
+
+ # cd /sys/kernel/debug/tracing/events/sched
+ # echo 0 > filter
+ # cat sched_switch/filter
+ none
+ # cat sched_wakeup/filter
+ none
+
+Set a filter using only common fields for all events in the sched
+subsystem (all events end up with the same filter)::
+
+ # cd /sys/kernel/debug/tracing/events/sched
+ # echo common_pid == 0 > filter
+ # cat sched_switch/filter
+ common_pid == 0
+ # cat sched_wakeup/filter
+ common_pid == 0
+
+Attempt to set a filter using a non-common field for all events in the
+sched subsystem (all events but those that have a prev_pid field retain
+their old filters)::
+
+ # cd /sys/kernel/debug/tracing/events/sched
+ # echo prev_pid == 0 > filter
+ # cat sched_switch/filter
+ prev_pid == 0
+ # cat sched_wakeup/filter
+ common_pid == 0
+
+5.4 PID filtering
+-----------------
+
+The set_event_pid file in the same directory as the top events directory
+exists, will filter all events from tracing any task that does not have the
+PID listed in the set_event_pid file.
+::
+
+ # cd /sys/kernel/debug/tracing
+ # echo $$ > set_event_pid
+ # echo 1 > events/enable
+
+Will only trace events for the current task.
+
+To add more PIDs without losing the PIDs already included, use '>>'.
+::
+
+ # echo 123 244 1 >> set_event_pid
+
+
+6. Event triggers
+=================
+
+Trace events can be made to conditionally invoke trigger 'commands'
+which can take various forms and are described in detail below;
+examples would be enabling or disabling other trace events or invoking
+a stack trace whenever the trace event is hit. Whenever a trace event
+with attached triggers is invoked, the set of trigger commands
+associated with that event is invoked. Any given trigger can
+additionally have an event filter of the same form as described in
+section 5 (Event filtering) associated with it - the command will only
+be invoked if the event being invoked passes the associated filter.
+If no filter is associated with the trigger, it always passes.
+
+Triggers are added to and removed from a particular event by writing
+trigger expressions to the 'trigger' file for the given event.
+
+A given event can have any number of triggers associated with it,
+subject to any restrictions that individual commands may have in that
+regard.
+
+Event triggers are implemented on top of "soft" mode, which means that
+whenever a trace event has one or more triggers associated with it,
+the event is activated even if it isn't actually enabled, but is
+disabled in a "soft" mode. That is, the tracepoint will be called,
+but just will not be traced, unless of course it's actually enabled.
+This scheme allows triggers to be invoked even for events that aren't
+enabled, and also allows the current event filter implementation to be
+used for conditionally invoking triggers.
+
+The syntax for event triggers is roughly based on the syntax for
+set_ftrace_filter 'ftrace filter commands' (see the 'Filter commands'
+section of Documentation/trace/ftrace.txt), but there are major
+differences and the implementation isn't currently tied to it in any
+way, so beware about making generalizations between the two.
+
+6.1 Expression syntax
+---------------------
+
+Triggers are added by echoing the command to the 'trigger' file::
+
+ # echo 'command[:count] [if filter]' > trigger
+
+Triggers are removed by echoing the same command but starting with '!'
+to the 'trigger' file::
+
+ # echo '!command[:count] [if filter]' > trigger
+
+The [if filter] part isn't used in matching commands when removing, so
+leaving that off in a '!' command will accomplish the same thing as
+having it in.
+
+The filter syntax is the same as that described in the 'Event
+filtering' section above.
+
+For ease of use, writing to the trigger file using '>' currently just
+adds or removes a single trigger and there's no explicit '>>' support
+('>' actually behaves like '>>') or truncation support to remove all
+triggers (you have to use '!' for each one added.)
+
+6.2 Supported trigger commands
+------------------------------
+
+The following commands are supported:
+
+- enable_event/disable_event
+
+ These commands can enable or disable another trace event whenever
+ the triggering event is hit. When these commands are registered,
+ the other trace event is activated, but disabled in a "soft" mode.
+ That is, the tracepoint will be called, but just will not be traced.
+ The event tracepoint stays in this mode as long as there's a trigger
+ in effect that can trigger it.
+
+ For example, the following trigger causes kmalloc events to be
+ traced when a read system call is entered, and the :1 at the end
+ specifies that this enablement happens only once::
+
+ # echo 'enable_event:kmem:kmalloc:1' > \
+ /sys/kernel/debug/tracing/events/syscalls/sys_enter_read/trigger
+
+ The following trigger causes kmalloc events to stop being traced
+ when a read system call exits. This disablement happens on every
+ read system call exit::
+
+ # echo 'disable_event:kmem:kmalloc' > \
+ /sys/kernel/debug/tracing/events/syscalls/sys_exit_read/trigger
+
+ The format is::
+
+ enable_event:<system>:<event>[:count]
+ disable_event:<system>:<event>[:count]
+
+ To remove the above commands::
+
+ # echo '!enable_event:kmem:kmalloc:1' > \
+ /sys/kernel/debug/tracing/events/syscalls/sys_enter_read/trigger
+
+ # echo '!disable_event:kmem:kmalloc' > \
+ /sys/kernel/debug/tracing/events/syscalls/sys_exit_read/trigger
+
+ Note that there can be any number of enable/disable_event triggers
+ per triggering event, but there can only be one trigger per
+ triggered event. e.g. sys_enter_read can have triggers enabling both
+ kmem:kmalloc and sched:sched_switch, but can't have two kmem:kmalloc
+ versions such as kmem:kmalloc and kmem:kmalloc:1 or 'kmem:kmalloc if
+ bytes_req == 256' and 'kmem:kmalloc if bytes_alloc == 256' (they
+ could be combined into a single filter on kmem:kmalloc though).
+
+- stacktrace
+
+ This command dumps a stacktrace in the trace buffer whenever the
+ triggering event occurs.
+
+ For example, the following trigger dumps a stacktrace every time the
+ kmalloc tracepoint is hit::
+
+ # echo 'stacktrace' > \
+ /sys/kernel/debug/tracing/events/kmem/kmalloc/trigger
+
+ The following trigger dumps a stacktrace the first 5 times a kmalloc
+ request happens with a size >= 64K::
+
+ # echo 'stacktrace:5 if bytes_req >= 65536' > \
+ /sys/kernel/debug/tracing/events/kmem/kmalloc/trigger
+
+ The format is::
+
+ stacktrace[:count]
+
+ To remove the above commands::
+
+ # echo '!stacktrace' > \
+ /sys/kernel/debug/tracing/events/kmem/kmalloc/trigger
+
+ # echo '!stacktrace:5 if bytes_req >= 65536' > \
+ /sys/kernel/debug/tracing/events/kmem/kmalloc/trigger
+
+ The latter can also be removed more simply by the following (without
+ the filter)::
+
+ # echo '!stacktrace:5' > \
+ /sys/kernel/debug/tracing/events/kmem/kmalloc/trigger
+
+ Note that there can be only one stacktrace trigger per triggering
+ event.
+
+- snapshot
+
+ This command causes a snapshot to be triggered whenever the
+ triggering event occurs.
+
+ The following command creates a snapshot every time a block request
+ queue is unplugged with a depth > 1. If you were tracing a set of
+ events or functions at the time, the snapshot trace buffer would
+ capture those events when the trigger event occurred::
+
+ # echo 'snapshot if nr_rq > 1' > \
+ /sys/kernel/debug/tracing/events/block/block_unplug/trigger
+
+ To only snapshot once::
+
+ # echo 'snapshot:1 if nr_rq > 1' > \
+ /sys/kernel/debug/tracing/events/block/block_unplug/trigger
+
+ To remove the above commands::
+
+ # echo '!snapshot if nr_rq > 1' > \
+ /sys/kernel/debug/tracing/events/block/block_unplug/trigger
+
+ # echo '!snapshot:1 if nr_rq > 1' > \
+ /sys/kernel/debug/tracing/events/block/block_unplug/trigger
+
+ Note that there can be only one snapshot trigger per triggering
+ event.
+
+- traceon/traceoff
+
+ These commands turn tracing on and off when the specified events are
+ hit. The parameter determines how many times the tracing system is
+ turned on and off. If unspecified, there is no limit.
+
+ The following command turns tracing off the first time a block
+ request queue is unplugged with a depth > 1. If you were tracing a
+ set of events or functions at the time, you could then examine the
+ trace buffer to see the sequence of events that led up to the
+ trigger event::
+
+ # echo 'traceoff:1 if nr_rq > 1' > \
+ /sys/kernel/debug/tracing/events/block/block_unplug/trigger
+
+ To always disable tracing when nr_rq > 1::
+
+ # echo 'traceoff if nr_rq > 1' > \
+ /sys/kernel/debug/tracing/events/block/block_unplug/trigger
+
+ To remove the above commands::
+
+ # echo '!traceoff:1 if nr_rq > 1' > \
+ /sys/kernel/debug/tracing/events/block/block_unplug/trigger
+
+ # echo '!traceoff if nr_rq > 1' > \
+ /sys/kernel/debug/tracing/events/block/block_unplug/trigger
+
+ Note that there can be only one traceon or traceoff trigger per
+ triggering event.
+
+- hist
+
+ This command aggregates event hits into a hash table keyed on one or
+ more trace event format fields (or stacktrace) and a set of running
+ totals derived from one or more trace event format fields and/or
+ event counts (hitcount).
+
+ The format of a hist trigger is as follows::
+
+ hist:keys=<field1[,field2,...]>[:values=<field1[,field2,...]>]
+ [:sort=<field1[,field2,...]>][:size=#entries][:pause][:continue]
+ [:clear][:name=histname1] [if <filter>]
+
+ When a matching event is hit, an entry is added to a hash table
+ using the key(s) and value(s) named. Keys and values correspond to
+ fields in the event's format description. Values must correspond to
+ numeric fields - on an event hit, the value(s) will be added to a
+ sum kept for that field. The special string 'hitcount' can be used
+ in place of an explicit value field - this is simply a count of
+ event hits. If 'values' isn't specified, an implicit 'hitcount'
+ value will be automatically created and used as the only value.
+ Keys can be any field, or the special string 'stacktrace', which
+ will use the event's kernel stacktrace as the key. The keywords
+ 'keys' or 'key' can be used to specify keys, and the keywords
+ 'values', 'vals', or 'val' can be used to specify values. Compound
+ keys consisting of up to two fields can be specified by the 'keys'
+ keyword. Hashing a compound key produces a unique entry in the
+ table for each unique combination of component keys, and can be
+ useful for providing more fine-grained summaries of event data.
+ Additionally, sort keys consisting of up to two fields can be
+ specified by the 'sort' keyword. If more than one field is
+ specified, the result will be a 'sort within a sort': the first key
+ is taken to be the primary sort key and the second the secondary
+ key. If a hist trigger is given a name using the 'name' parameter,
+ its histogram data will be shared with other triggers of the same
+ name, and trigger hits will update this common data. Only triggers
+ with 'compatible' fields can be combined in this way; triggers are
+ 'compatible' if the fields named in the trigger share the same
+ number and type of fields and those fields also have the same names.
+ Note that any two events always share the compatible 'hitcount' and
+ 'stacktrace' fields and can therefore be combined using those
+ fields, however pointless that may be.
+
+ 'hist' triggers add a 'hist' file to each event's subdirectory.
+ Reading the 'hist' file for the event will dump the hash table in
+ its entirety to stdout. If there are multiple hist triggers
+ attached to an event, there will be a table for each trigger in the
+ output. The table displayed for a named trigger will be the same as
+ any other instance having the same name. Each printed hash table
+ entry is a simple list of the keys and values comprising the entry;
+ keys are printed first and are delineated by curly braces, and are
+ followed by the set of value fields for the entry. By default,
+ numeric fields are displayed as base-10 integers. This can be
+ modified by appending any of the following modifiers to the field
+ name:
+
+ - .hex display a number as a hex value
+ - .sym display an address as a symbol
+ - .sym-offset display an address as a symbol and offset
+ - .syscall display a syscall id as a system call name
+ - .execname display a common_pid as a program name
+
+ Note that in general the semantics of a given field aren't
+ interpreted when applying a modifier to it, but there are some
+ restrictions to be aware of in this regard:
+
+ - only the 'hex' modifier can be used for values (because values
+ are essentially sums, and the other modifiers don't make sense
+ in that context).
+ - the 'execname' modifier can only be used on a 'common_pid'. The
+ reason for this is that the execname is simply the 'comm' value
+ saved for the 'current' process when an event was triggered,
+ which is the same as the common_pid value saved by the event
+ tracing code. Trying to apply that comm value to other pid
+ values wouldn't be correct, and typically events that care save
+ pid-specific comm fields in the event itself.
+
+ A typical usage scenario would be the following to enable a hist
+ trigger, read its current contents, and then turn it off::
+
+ # echo 'hist:keys=skbaddr.hex:vals=len' > \
+ /sys/kernel/debug/tracing/events/net/netif_rx/trigger
+
+ # cat /sys/kernel/debug/tracing/events/net/netif_rx/hist
+
+ # echo '!hist:keys=skbaddr.hex:vals=len' > \
+ /sys/kernel/debug/tracing/events/net/netif_rx/trigger
+
+ The trigger file itself can be read to show the details of the
+ currently attached hist trigger. This information is also displayed
+ at the top of the 'hist' file when read.
+
+ By default, the size of the hash table is 2048 entries. The 'size'
+ parameter can be used to specify more or fewer than that. The units
+ are in terms of hashtable entries - if a run uses more entries than
+ specified, the results will show the number of 'drops', the number
+ of hits that were ignored. The size should be a power of 2 between
+ 128 and 131072 (any non- power-of-2 number specified will be rounded
+ up).
+
+ The 'sort' parameter can be used to specify a value field to sort
+ on. The default if unspecified is 'hitcount' and the default sort
+ order is 'ascending'. To sort in the opposite direction, append
+ .descending' to the sort key.
+
+ The 'pause' parameter can be used to pause an existing hist trigger
+ or to start a hist trigger but not log any events until told to do
+ so. 'continue' or 'cont' can be used to start or restart a paused
+ hist trigger.
+
+ The 'clear' parameter will clear the contents of a running hist
+ trigger and leave its current paused/active state.
+
+ Note that the 'pause', 'cont', and 'clear' parameters should be
+ applied using 'append' shell operator ('>>') if applied to an
+ existing trigger, rather than via the '>' operator, which will cause
+ the trigger to be removed through truncation.
+
+- enable_hist/disable_hist
+
+ The enable_hist and disable_hist triggers can be used to have one
+ event conditionally start and stop another event's already-attached
+ hist trigger. Any number of enable_hist and disable_hist triggers
+ can be attached to a given event, allowing that event to kick off
+ and stop aggregations on a host of other events.
+
+ The format is very similar to the enable/disable_event triggers::
+
+ enable_hist:<system>:<event>[:count]
+ disable_hist:<system>:<event>[:count]
+
+ Instead of enabling or disabling the tracing of the target event
+ into the trace buffer as the enable/disable_event triggers do, the
+ enable/disable_hist triggers enable or disable the aggregation of
+ the target event into a hash table.
+
+ A typical usage scenario for the enable_hist/disable_hist triggers
+ would be to first set up a paused hist trigger on some event,
+ followed by an enable_hist/disable_hist pair that turns the hist
+ aggregation on and off when conditions of interest are hit::
+
+ # echo 'hist:keys=skbaddr.hex:vals=len:pause' > \
+ /sys/kernel/debug/tracing/events/net/netif_receive_skb/trigger
+
+ # echo 'enable_hist:net:netif_receive_skb if filename==/usr/bin/wget' > \
+ /sys/kernel/debug/tracing/events/sched/sched_process_exec/trigger
+
+ # echo 'disable_hist:net:netif_receive_skb if comm==wget' > \
+ /sys/kernel/debug/tracing/events/sched/sched_process_exit/trigger
+
+ The above sets up an initially paused hist trigger which is unpaused
+ and starts aggregating events when a given program is executed, and
+ which stops aggregating when the process exits and the hist trigger
+ is paused again.
+
+ The examples below provide a more concrete illustration of the
+ concepts and typical usage patterns discussed above.
+
+
+6.2 'hist' trigger examples
+---------------------------
+
+ The first set of examples creates aggregations using the kmalloc
+ event. The fields that can be used for the hist trigger are listed
+ in the kmalloc event's format file::
+
+ # cat /sys/kernel/debug/tracing/events/kmem/kmalloc/format
+ name: kmalloc
+ ID: 374
+ format:
+ field:unsigned short common_type; offset:0; size:2; signed:0;
+ field:unsigned char common_flags; offset:2; size:1; signed:0;
+ field:unsigned char common_preempt_count; offset:3; size:1; signed:0;
+ field:int common_pid; offset:4; size:4; signed:1;
+
+ field:unsigned long call_site; offset:8; size:8; signed:0;
+ field:const void * ptr; offset:16; size:8; signed:0;
+ field:size_t bytes_req; offset:24; size:8; signed:0;
+ field:size_t bytes_alloc; offset:32; size:8; signed:0;
+ field:gfp_t gfp_flags; offset:40; size:4; signed:0;
+
+ We'll start by creating a hist trigger that generates a simple table
+ that lists the total number of bytes requested for each function in
+ the kernel that made one or more calls to kmalloc::
+
+ # echo 'hist:key=call_site:val=bytes_req' > \
+ /sys/kernel/debug/tracing/events/kmem/kmalloc/trigger
+
+ This tells the tracing system to create a 'hist' trigger using the
+ call_site field of the kmalloc event as the key for the table, which
+ just means that each unique call_site address will have an entry
+ created for it in the table. The 'val=bytes_req' parameter tells
+ the hist trigger that for each unique entry (call_site) in the
+ table, it should keep a running total of the number of bytes
+ requested by that call_site.
+
+ We'll let it run for awhile and then dump the contents of the 'hist'
+ file in the kmalloc event's subdirectory (for readability, a number
+ of entries have been omitted)::
+
+ # cat /sys/kernel/debug/tracing/events/kmem/kmalloc/hist
+ # trigger info: hist:keys=call_site:vals=bytes_req:sort=hitcount:size=2048 [active]
+
+ { call_site: 18446744072106379007 } hitcount: 1 bytes_req: 176
+ { call_site: 18446744071579557049 } hitcount: 1 bytes_req: 1024
+ { call_site: 18446744071580608289 } hitcount: 1 bytes_req: 16384
+ { call_site: 18446744071581827654 } hitcount: 1 bytes_req: 24
+ { call_site: 18446744071580700980 } hitcount: 1 bytes_req: 8
+ { call_site: 18446744071579359876 } hitcount: 1 bytes_req: 152
+ { call_site: 18446744071580795365 } hitcount: 3 bytes_req: 144
+ { call_site: 18446744071581303129 } hitcount: 3 bytes_req: 144
+ { call_site: 18446744071580713234 } hitcount: 4 bytes_req: 2560
+ { call_site: 18446744071580933750 } hitcount: 4 bytes_req: 736
+ .
+ .
+ .
+ { call_site: 18446744072106047046 } hitcount: 69 bytes_req: 5576
+ { call_site: 18446744071582116407 } hitcount: 73 bytes_req: 2336
+ { call_site: 18446744072106054684 } hitcount: 136 bytes_req: 140504
+ { call_site: 18446744072106224230 } hitcount: 136 bytes_req: 19584
+ { call_site: 18446744072106078074 } hitcount: 153 bytes_req: 2448
+ { call_site: 18446744072106062406 } hitcount: 153 bytes_req: 36720
+ { call_site: 18446744071582507929 } hitcount: 153 bytes_req: 37088
+ { call_site: 18446744072102520590 } hitcount: 273 bytes_req: 10920
+ { call_site: 18446744071582143559 } hitcount: 358 bytes_req: 716
+ { call_site: 18446744072106465852 } hitcount: 417 bytes_req: 56712
+ { call_site: 18446744072102523378 } hitcount: 485 bytes_req: 27160
+ { call_site: 18446744072099568646 } hitcount: 1676 bytes_req: 33520
+
+ Totals:
+ Hits: 4610
+ Entries: 45
+ Dropped: 0
+
+ The output displays a line for each entry, beginning with the key
+ specified in the trigger, followed by the value(s) also specified in
+ the trigger. At the beginning of the output is a line that displays
+ the trigger info, which can also be displayed by reading the
+ 'trigger' file::
+
+ # cat /sys/kernel/debug/tracing/events/kmem/kmalloc/trigger
+ hist:keys=call_site:vals=bytes_req:sort=hitcount:size=2048 [active]
+
+ At the end of the output are a few lines that display the overall
+ totals for the run. The 'Hits' field shows the total number of
+ times the event trigger was hit, the 'Entries' field shows the total
+ number of used entries in the hash table, and the 'Dropped' field
+ shows the number of hits that were dropped because the number of
+ used entries for the run exceeded the maximum number of entries
+ allowed for the table (normally 0, but if not a hint that you may
+ want to increase the size of the table using the 'size' parameter).
+
+ Notice in the above output that there's an extra field, 'hitcount',
+ which wasn't specified in the trigger. Also notice that in the
+ trigger info output, there's a parameter, 'sort=hitcount', which
+ wasn't specified in the trigger either. The reason for that is that
+ every trigger implicitly keeps a count of the total number of hits
+ attributed to a given entry, called the 'hitcount'. That hitcount
+ information is explicitly displayed in the output, and in the
+ absence of a user-specified sort parameter, is used as the default
+ sort field.
+
+ The value 'hitcount' can be used in place of an explicit value in
+ the 'values' parameter if you don't really need to have any
+ particular field summed and are mainly interested in hit
+ frequencies.
+
+ To turn the hist trigger off, simply call up the trigger in the
+ command history and re-execute it with a '!' prepended::
+
+ # echo '!hist:key=call_site:val=bytes_req' > \
+ /sys/kernel/debug/tracing/events/kmem/kmalloc/trigger
+
+ Finally, notice that the call_site as displayed in the output above
+ isn't really very useful. It's an address, but normally addresses
+ are displayed in hex. To have a numeric field displayed as a hex
+ value, simply append '.hex' to the field name in the trigger::
+
+ # echo 'hist:key=call_site.hex:val=bytes_req' > \
+ /sys/kernel/debug/tracing/events/kmem/kmalloc/trigger
+
+ # cat /sys/kernel/debug/tracing/events/kmem/kmalloc/hist
+ # trigger info: hist:keys=call_site.hex:vals=bytes_req:sort=hitcount:size=2048 [active]
+
+ { call_site: ffffffffa026b291 } hitcount: 1 bytes_req: 433
+ { call_site: ffffffffa07186ff } hitcount: 1 bytes_req: 176
+ { call_site: ffffffff811ae721 } hitcount: 1 bytes_req: 16384
+ { call_site: ffffffff811c5134 } hitcount: 1 bytes_req: 8
+ { call_site: ffffffffa04a9ebb } hitcount: 1 bytes_req: 511
+ { call_site: ffffffff8122e0a6 } hitcount: 1 bytes_req: 12
+ { call_site: ffffffff8107da84 } hitcount: 1 bytes_req: 152
+ { call_site: ffffffff812d8246 } hitcount: 1 bytes_req: 24
+ { call_site: ffffffff811dc1e5 } hitcount: 3 bytes_req: 144
+ { call_site: ffffffffa02515e8 } hitcount: 3 bytes_req: 648
+ { call_site: ffffffff81258159 } hitcount: 3 bytes_req: 144
+ { call_site: ffffffff811c80f4 } hitcount: 4 bytes_req: 544
+ .
+ .
+ .
+ { call_site: ffffffffa06c7646 } hitcount: 106 bytes_req: 8024
+ { call_site: ffffffffa06cb246 } hitcount: 132 bytes_req: 31680
+ { call_site: ffffffffa06cef7a } hitcount: 132 bytes_req: 2112
+ { call_site: ffffffff8137e399 } hitcount: 132 bytes_req: 23232
+ { call_site: ffffffffa06c941c } hitcount: 185 bytes_req: 171360
+ { call_site: ffffffffa06f2a66 } hitcount: 185 bytes_req: 26640
+ { call_site: ffffffffa036a70e } hitcount: 265 bytes_req: 10600
+ { call_site: ffffffff81325447 } hitcount: 292 bytes_req: 584
+ { call_site: ffffffffa072da3c } hitcount: 446 bytes_req: 60656
+ { call_site: ffffffffa036b1f2 } hitcount: 526 bytes_req: 29456
+ { call_site: ffffffffa0099c06 } hitcount: 1780 bytes_req: 35600
+
+ Totals:
+ Hits: 4775
+ Entries: 46
+ Dropped: 0
+
+ Even that's only marginally more useful - while hex values do look
+ more like addresses, what users are typically more interested in
+ when looking at text addresses are the corresponding symbols
+ instead. To have an address displayed as symbolic value instead,
+ simply append '.sym' or '.sym-offset' to the field name in the
+ trigger::
+
+ # echo 'hist:key=call_site.sym:val=bytes_req' > \
+ /sys/kernel/debug/tracing/events/kmem/kmalloc/trigger
+
+ # cat /sys/kernel/debug/tracing/events/kmem/kmalloc/hist
+ # trigger info: hist:keys=call_site.sym:vals=bytes_req:sort=hitcount:size=2048 [active]
+
+ { call_site: [ffffffff810adcb9] syslog_print_all } hitcount: 1 bytes_req: 1024
+ { call_site: [ffffffff8154bc62] usb_control_msg } hitcount: 1 bytes_req: 8
+ { call_site: [ffffffffa00bf6fe] hidraw_send_report [hid] } hitcount: 1 bytes_req: 7
+ { call_site: [ffffffff8154acbe] usb_alloc_urb } hitcount: 1 bytes_req: 192
+ { call_site: [ffffffffa00bf1ca] hidraw_report_event [hid] } hitcount: 1 bytes_req: 7
+ { call_site: [ffffffff811e3a25] __seq_open_private } hitcount: 1 bytes_req: 40
+ { call_site: [ffffffff8109524a] alloc_fair_sched_group } hitcount: 2 bytes_req: 128
+ { call_site: [ffffffff811febd5] fsnotify_alloc_group } hitcount: 2 bytes_req: 528
+ { call_site: [ffffffff81440f58] __tty_buffer_request_room } hitcount: 2 bytes_req: 2624
+ { call_site: [ffffffff81200ba6] inotify_new_group } hitcount: 2 bytes_req: 96
+ { call_site: [ffffffffa05e19af] ieee80211_start_tx_ba_session [mac80211] } hitcount: 2 bytes_req: 464
+ { call_site: [ffffffff81672406] tcp_get_metrics } hitcount: 2 bytes_req: 304
+ { call_site: [ffffffff81097ec2] alloc_rt_sched_group } hitcount: 2 bytes_req: 128
+ { call_site: [ffffffff81089b05] sched_create_group } hitcount: 2 bytes_req: 1424
+ .
+ .
+ .
+ { call_site: [ffffffffa04a580c] intel_crtc_page_flip [i915] } hitcount: 1185 bytes_req: 123240
+ { call_site: [ffffffffa0287592] drm_mode_page_flip_ioctl [drm] } hitcount: 1185 bytes_req: 104280
+ { call_site: [ffffffffa04c4a3c] intel_plane_duplicate_state [i915] } hitcount: 1402 bytes_req: 190672
+ { call_site: [ffffffff812891ca] ext4_find_extent } hitcount: 1518 bytes_req: 146208
+ { call_site: [ffffffffa029070e] drm_vma_node_allow [drm] } hitcount: 1746 bytes_req: 69840
+ { call_site: [ffffffffa045e7c4] i915_gem_do_execbuffer.isra.23 [i915] } hitcount: 2021 bytes_req: 792312
+ { call_site: [ffffffffa02911f2] drm_modeset_lock_crtc [drm] } hitcount: 2592 bytes_req: 145152
+ { call_site: [ffffffffa0489a66] intel_ring_begin [i915] } hitcount: 2629 bytes_req: 378576
+ { call_site: [ffffffffa046041c] i915_gem_execbuffer2 [i915] } hitcount: 2629 bytes_req: 3783248
+ { call_site: [ffffffff81325607] apparmor_file_alloc_security } hitcount: 5192 bytes_req: 10384
+ { call_site: [ffffffffa00b7c06] hid_report_raw_event [hid] } hitcount: 5529 bytes_req: 110584
+ { call_site: [ffffffff8131ebf7] aa_alloc_task_context } hitcount: 21943 bytes_req: 702176
+ { call_site: [ffffffff8125847d] ext4_htree_store_dirent } hitcount: 55759 bytes_req: 5074265
+
+ Totals:
+ Hits: 109928
+ Entries: 71
+ Dropped: 0
+
+ Because the default sort key above is 'hitcount', the above shows a
+ the list of call_sites by increasing hitcount, so that at the bottom
+ we see the functions that made the most kmalloc calls during the
+ run. If instead we we wanted to see the top kmalloc callers in
+ terms of the number of bytes requested rather than the number of
+ calls, and we wanted the top caller to appear at the top, we can use
+ the 'sort' parameter, along with the 'descending' modifier::
+
+ # echo 'hist:key=call_site.sym:val=bytes_req:sort=bytes_req.descending' > \
+ /sys/kernel/debug/tracing/events/kmem/kmalloc/trigger
+
+ # cat /sys/kernel/debug/tracing/events/kmem/kmalloc/hist
+ # trigger info: hist:keys=call_site.sym:vals=bytes_req:sort=bytes_req.descending:size=2048 [active]
+
+ { call_site: [ffffffffa046041c] i915_gem_execbuffer2 [i915] } hitcount: 2186 bytes_req: 3397464
+ { call_site: [ffffffffa045e7c4] i915_gem_do_execbuffer.isra.23 [i915] } hitcount: 1790 bytes_req: 712176
+ { call_site: [ffffffff8125847d] ext4_htree_store_dirent } hitcount: 8132 bytes_req: 513135
+ { call_site: [ffffffff811e2a1b] seq_buf_alloc } hitcount: 106 bytes_req: 440128
+ { call_site: [ffffffffa0489a66] intel_ring_begin [i915] } hitcount: 2186 bytes_req: 314784
+ { call_site: [ffffffff812891ca] ext4_find_extent } hitcount: 2174 bytes_req: 208992
+ { call_site: [ffffffff811ae8e1] __kmalloc } hitcount: 8 bytes_req: 131072
+ { call_site: [ffffffffa04c4a3c] intel_plane_duplicate_state [i915] } hitcount: 859 bytes_req: 116824
+ { call_site: [ffffffffa02911f2] drm_modeset_lock_crtc [drm] } hitcount: 1834 bytes_req: 102704
+ { call_site: [ffffffffa04a580c] intel_crtc_page_flip [i915] } hitcount: 972 bytes_req: 101088
+ { call_site: [ffffffffa0287592] drm_mode_page_flip_ioctl [drm] } hitcount: 972 bytes_req: 85536
+ { call_site: [ffffffffa00b7c06] hid_report_raw_event [hid] } hitcount: 3333 bytes_req: 66664
+ { call_site: [ffffffff8137e559] sg_kmalloc } hitcount: 209 bytes_req: 61632
+ .
+ .
+ .
+ { call_site: [ffffffff81095225] alloc_fair_sched_group } hitcount: 2 bytes_req: 128
+ { call_site: [ffffffff81097ec2] alloc_rt_sched_group } hitcount: 2 bytes_req: 128
+ { call_site: [ffffffff812d8406] copy_semundo } hitcount: 2 bytes_req: 48
+ { call_site: [ffffffff81200ba6] inotify_new_group } hitcount: 1 bytes_req: 48
+ { call_site: [ffffffffa027121a] drm_getmagic [drm] } hitcount: 1 bytes_req: 48
+ { call_site: [ffffffff811e3a25] __seq_open_private } hitcount: 1 bytes_req: 40
+ { call_site: [ffffffff811c52f4] bprm_change_interp } hitcount: 2 bytes_req: 16
+ { call_site: [ffffffff8154bc62] usb_control_msg } hitcount: 1 bytes_req: 8
+ { call_site: [ffffffffa00bf1ca] hidraw_report_event [hid] } hitcount: 1 bytes_req: 7
+ { call_site: [ffffffffa00bf6fe] hidraw_send_report [hid] } hitcount: 1 bytes_req: 7
+
+ Totals:
+ Hits: 32133
+ Entries: 81
+ Dropped: 0
+
+ To display the offset and size information in addition to the symbol
+ name, just use 'sym-offset' instead::
+
+ # echo 'hist:key=call_site.sym-offset:val=bytes_req:sort=bytes_req.descending' > \
+ /sys/kernel/debug/tracing/events/kmem/kmalloc/trigger
+
+ # cat /sys/kernel/debug/tracing/events/kmem/kmalloc/hist
+ # trigger info: hist:keys=call_site.sym-offset:vals=bytes_req:sort=bytes_req.descending:size=2048 [active]
+
+ { call_site: [ffffffffa046041c] i915_gem_execbuffer2+0x6c/0x2c0 [i915] } hitcount: 4569 bytes_req: 3163720
+ { call_site: [ffffffffa0489a66] intel_ring_begin+0xc6/0x1f0 [i915] } hitcount: 4569 bytes_req: 657936
+ { call_site: [ffffffffa045e7c4] i915_gem_do_execbuffer.isra.23+0x694/0x1020 [i915] } hitcount: 1519 bytes_req: 472936
+ { call_site: [ffffffffa045e646] i915_gem_do_execbuffer.isra.23+0x516/0x1020 [i915] } hitcount: 3050 bytes_req: 211832
+ { call_site: [ffffffff811e2a1b] seq_buf_alloc+0x1b/0x50 } hitcount: 34 bytes_req: 148384
+ { call_site: [ffffffffa04a580c] intel_crtc_page_flip+0xbc/0x870 [i915] } hitcount: 1385 bytes_req: 144040
+ { call_site: [ffffffff811ae8e1] __kmalloc+0x191/0x1b0 } hitcount: 8 bytes_req: 131072
+ { call_site: [ffffffffa0287592] drm_mode_page_flip_ioctl+0x282/0x360 [drm] } hitcount: 1385 bytes_req: 121880
+ { call_site: [ffffffffa02911f2] drm_modeset_lock_crtc+0x32/0x100 [drm] } hitcount: 1848 bytes_req: 103488
+ { call_site: [ffffffffa04c4a3c] intel_plane_duplicate_state+0x2c/0xa0 [i915] } hitcount: 461 bytes_req: 62696
+ { call_site: [ffffffffa029070e] drm_vma_node_allow+0x2e/0xd0 [drm] } hitcount: 1541 bytes_req: 61640
+ { call_site: [ffffffff815f8d7b] sk_prot_alloc+0xcb/0x1b0 } hitcount: 57 bytes_req: 57456
+ .
+ .
+ .
+ { call_site: [ffffffff8109524a] alloc_fair_sched_group+0x5a/0x1a0 } hitcount: 2 bytes_req: 128
+ { call_site: [ffffffffa027b921] drm_vm_open_locked+0x31/0xa0 [drm] } hitcount: 3 bytes_req: 96
+ { call_site: [ffffffff8122e266] proc_self_follow_link+0x76/0xb0 } hitcount: 8 bytes_req: 96
+ { call_site: [ffffffff81213e80] load_elf_binary+0x240/0x1650 } hitcount: 3 bytes_req: 84
+ { call_site: [ffffffff8154bc62] usb_control_msg+0x42/0x110 } hitcount: 1 bytes_req: 8
+ { call_site: [ffffffffa00bf6fe] hidraw_send_report+0x7e/0x1a0 [hid] } hitcount: 1 bytes_req: 7
+ { call_site: [ffffffffa00bf1ca] hidraw_report_event+0x8a/0x120 [hid] } hitcount: 1 bytes_req: 7
+
+ Totals:
+ Hits: 26098
+ Entries: 64
+ Dropped: 0
+
+ We can also add multiple fields to the 'values' parameter. For
+ example, we might want to see the total number of bytes allocated
+ alongside bytes requested, and display the result sorted by bytes
+ allocated in a descending order::
+
+ # echo 'hist:keys=call_site.sym:values=bytes_req,bytes_alloc:sort=bytes_alloc.descending' > \
+ /sys/kernel/debug/tracing/events/kmem/kmalloc/trigger
+
+ # cat /sys/kernel/debug/tracing/events/kmem/kmalloc/hist
+ # trigger info: hist:keys=call_site.sym:vals=bytes_req,bytes_alloc:sort=bytes_alloc.descending:size=2048 [active]
+
+ { call_site: [ffffffffa046041c] i915_gem_execbuffer2 [i915] } hitcount: 7403 bytes_req: 4084360 bytes_alloc: 5958016
+ { call_site: [ffffffff811e2a1b] seq_buf_alloc } hitcount: 541 bytes_req: 2213968 bytes_alloc: 2228224
+ { call_site: [ffffffffa0489a66] intel_ring_begin [i915] } hitcount: 7404 bytes_req: 1066176 bytes_alloc: 1421568
+ { call_site: [ffffffffa045e7c4] i915_gem_do_execbuffer.isra.23 [i915] } hitcount: 1565 bytes_req: 557368 bytes_alloc: 1037760
+ { call_site: [ffffffff8125847d] ext4_htree_store_dirent } hitcount: 9557 bytes_req: 595778 bytes_alloc: 695744
+ { call_site: [ffffffffa045e646] i915_gem_do_execbuffer.isra.23 [i915] } hitcount: 5839 bytes_req: 430680 bytes_alloc: 470400
+ { call_site: [ffffffffa04c4a3c] intel_plane_duplicate_state [i915] } hitcount: 2388 bytes_req: 324768 bytes_alloc: 458496
+ { call_site: [ffffffffa02911f2] drm_modeset_lock_crtc [drm] } hitcount: 3911 bytes_req: 219016 bytes_alloc: 250304
+ { call_site: [ffffffff815f8d7b] sk_prot_alloc } hitcount: 235 bytes_req: 236880 bytes_alloc: 240640
+ { call_site: [ffffffff8137e559] sg_kmalloc } hitcount: 557 bytes_req: 169024 bytes_alloc: 221760
+ { call_site: [ffffffffa00b7c06] hid_report_raw_event [hid] } hitcount: 9378 bytes_req: 187548 bytes_alloc: 206312
+ { call_site: [ffffffffa04a580c] intel_crtc_page_flip [i915] } hitcount: 1519 bytes_req: 157976 bytes_alloc: 194432
+ .
+ .
+ .
+ { call_site: [ffffffff8109bd3b] sched_autogroup_create_attach } hitcount: 2 bytes_req: 144 bytes_alloc: 192
+ { call_site: [ffffffff81097ee8] alloc_rt_sched_group } hitcount: 2 bytes_req: 128 bytes_alloc: 128
+ { call_site: [ffffffff8109524a] alloc_fair_sched_group } hitcount: 2 bytes_req: 128 bytes_alloc: 128
+ { call_site: [ffffffff81095225] alloc_fair_sched_group } hitcount: 2 bytes_req: 128 bytes_alloc: 128
+ { call_site: [ffffffff81097ec2] alloc_rt_sched_group } hitcount: 2 bytes_req: 128 bytes_alloc: 128
+ { call_site: [ffffffff81213e80] load_elf_binary } hitcount: 3 bytes_req: 84 bytes_alloc: 96
+ { call_site: [ffffffff81079a2e] kthread_create_on_node } hitcount: 1 bytes_req: 56 bytes_alloc: 64
+ { call_site: [ffffffffa00bf6fe] hidraw_send_report [hid] } hitcount: 1 bytes_req: 7 bytes_alloc: 8
+ { call_site: [ffffffff8154bc62] usb_control_msg } hitcount: 1 bytes_req: 8 bytes_alloc: 8
+ { call_site: [ffffffffa00bf1ca] hidraw_report_event [hid] } hitcount: 1 bytes_req: 7 bytes_alloc: 8
+
+ Totals:
+ Hits: 66598
+ Entries: 65
+ Dropped: 0
+
+ Finally, to finish off our kmalloc example, instead of simply having
+ the hist trigger display symbolic call_sites, we can have the hist
+ trigger additionally display the complete set of kernel stack traces
+ that led to each call_site. To do that, we simply use the special
+ value 'stacktrace' for the key parameter::
+
+ # echo 'hist:keys=stacktrace:values=bytes_req,bytes_alloc:sort=bytes_alloc' > \
+ /sys/kernel/debug/tracing/events/kmem/kmalloc/trigger
+
+ The above trigger will use the kernel stack trace in effect when an
+ event is triggered as the key for the hash table. This allows the
+ enumeration of every kernel callpath that led up to a particular
+ event, along with a running total of any of the event fields for
+ that event. Here we tally bytes requested and bytes allocated for
+ every callpath in the system that led up to a kmalloc (in this case
+ every callpath to a kmalloc for a kernel compile)::
+
+ # cat /sys/kernel/debug/tracing/events/kmem/kmalloc/hist
+ # trigger info: hist:keys=stacktrace:vals=bytes_req,bytes_alloc:sort=bytes_alloc:size=2048 [active]
+
+ { stacktrace:
+ __kmalloc_track_caller+0x10b/0x1a0
+ kmemdup+0x20/0x50
+ hidraw_report_event+0x8a/0x120 [hid]
+ hid_report_raw_event+0x3ea/0x440 [hid]
+ hid_input_report+0x112/0x190 [hid]
+ hid_irq_in+0xc2/0x260 [usbhid]
+ __usb_hcd_giveback_urb+0x72/0x120
+ usb_giveback_urb_bh+0x9e/0xe0
+ tasklet_hi_action+0xf8/0x100
+ __do_softirq+0x114/0x2c0
+ irq_exit+0xa5/0xb0
+ do_IRQ+0x5a/0xf0
+ ret_from_intr+0x0/0x30
+ cpuidle_enter+0x17/0x20
+ cpu_startup_entry+0x315/0x3e0
+ rest_init+0x7c/0x80
+ } hitcount: 3 bytes_req: 21 bytes_alloc: 24
+ { stacktrace:
+ __kmalloc_track_caller+0x10b/0x1a0
+ kmemdup+0x20/0x50
+ hidraw_report_event+0x8a/0x120 [hid]
+ hid_report_raw_event+0x3ea/0x440 [hid]
+ hid_input_report+0x112/0x190 [hid]
+ hid_irq_in+0xc2/0x260 [usbhid]
+ __usb_hcd_giveback_urb+0x72/0x120
+ usb_giveback_urb_bh+0x9e/0xe0
+ tasklet_hi_action+0xf8/0x100
+ __do_softirq+0x114/0x2c0
+ irq_exit+0xa5/0xb0
+ do_IRQ+0x5a/0xf0
+ ret_from_intr+0x0/0x30
+ } hitcount: 3 bytes_req: 21 bytes_alloc: 24
+ { stacktrace:
+ kmem_cache_alloc_trace+0xeb/0x150
+ aa_alloc_task_context+0x27/0x40
+ apparmor_cred_prepare+0x1f/0x50
+ security_prepare_creds+0x16/0x20
+ prepare_creds+0xdf/0x1a0
+ SyS_capset+0xb5/0x200
+ system_call_fastpath+0x12/0x6a
+ } hitcount: 1 bytes_req: 32 bytes_alloc: 32
+ .
+ .
+ .
+ { stacktrace:
+ __kmalloc+0x11b/0x1b0
+ i915_gem_execbuffer2+0x6c/0x2c0 [i915]
+ drm_ioctl+0x349/0x670 [drm]
+ do_vfs_ioctl+0x2f0/0x4f0
+ SyS_ioctl+0x81/0xa0
+ system_call_fastpath+0x12/0x6a
+ } hitcount: 17726 bytes_req: 13944120 bytes_alloc: 19593808
+ { stacktrace:
+ __kmalloc+0x11b/0x1b0
+ load_elf_phdrs+0x76/0xa0
+ load_elf_binary+0x102/0x1650
+ search_binary_handler+0x97/0x1d0
+ do_execveat_common.isra.34+0x551/0x6e0
+ SyS_execve+0x3a/0x50
+ return_from_execve+0x0/0x23
+ } hitcount: 33348 bytes_req: 17152128 bytes_alloc: 20226048
+ { stacktrace:
+ kmem_cache_alloc_trace+0xeb/0x150
+ apparmor_file_alloc_security+0x27/0x40
+ security_file_alloc+0x16/0x20
+ get_empty_filp+0x93/0x1c0
+ path_openat+0x31/0x5f0
+ do_filp_open+0x3a/0x90
+ do_sys_open+0x128/0x220
+ SyS_open+0x1e/0x20
+ system_call_fastpath+0x12/0x6a
+ } hitcount: 4766422 bytes_req: 9532844 bytes_alloc: 38131376
+ { stacktrace:
+ __kmalloc+0x11b/0x1b0
+ seq_buf_alloc+0x1b/0x50
+ seq_read+0x2cc/0x370
+ proc_reg_read+0x3d/0x80
+ __vfs_read+0x28/0xe0
+ vfs_read+0x86/0x140
+ SyS_read+0x46/0xb0
+ system_call_fastpath+0x12/0x6a
+ } hitcount: 19133 bytes_req: 78368768 bytes_alloc: 78368768
+
+ Totals:
+ Hits: 6085872
+ Entries: 253
+ Dropped: 0
+
+ If you key a hist trigger on common_pid, in order for example to
+ gather and display sorted totals for each process, you can use the
+ special .execname modifier to display the executable names for the
+ processes in the table rather than raw pids. The example below
+ keeps a per-process sum of total bytes read::
+
+ # echo 'hist:key=common_pid.execname:val=count:sort=count.descending' > \
+ /sys/kernel/debug/tracing/events/syscalls/sys_enter_read/trigger
+
+ # cat /sys/kernel/debug/tracing/events/syscalls/sys_enter_read/hist
+ # trigger info: hist:keys=common_pid.execname:vals=count:sort=count.descending:size=2048 [active]
+
+ { common_pid: gnome-terminal [ 3196] } hitcount: 280 count: 1093512
+ { common_pid: Xorg [ 1309] } hitcount: 525 count: 256640
+ { common_pid: compiz [ 2889] } hitcount: 59 count: 254400
+ { common_pid: bash [ 8710] } hitcount: 3 count: 66369
+ { common_pid: dbus-daemon-lau [ 8703] } hitcount: 49 count: 47739
+ { common_pid: irqbalance [ 1252] } hitcount: 27 count: 27648
+ { common_pid: 01ifupdown [ 8705] } hitcount: 3 count: 17216
+ { common_pid: dbus-daemon [ 772] } hitcount: 10 count: 12396
+ { common_pid: Socket Thread [ 8342] } hitcount: 11 count: 11264
+ { common_pid: nm-dhcp-client. [ 8701] } hitcount: 6 count: 7424
+ { common_pid: gmain [ 1315] } hitcount: 18 count: 6336
+ .
+ .
+ .
+ { common_pid: postgres [ 1892] } hitcount: 2 count: 32
+ { common_pid: postgres [ 1891] } hitcount: 2 count: 32
+ { common_pid: gmain [ 8704] } hitcount: 2 count: 32
+ { common_pid: upstart-dbus-br [ 2740] } hitcount: 21 count: 21
+ { common_pid: nm-dispatcher.a [ 8696] } hitcount: 1 count: 16
+ { common_pid: indicator-datet [ 2904] } hitcount: 1 count: 16
+ { common_pid: gdbus [ 2998] } hitcount: 1 count: 16
+ { common_pid: rtkit-daemon [ 2052] } hitcount: 1 count: 8
+ { common_pid: init [ 1] } hitcount: 2 count: 2
+
+ Totals:
+ Hits: 2116
+ Entries: 51
+ Dropped: 0
+
+ Similarly, if you key a hist trigger on syscall id, for example to
+ gather and display a list of systemwide syscall hits, you can use
+ the special .syscall modifier to display the syscall names rather
+ than raw ids. The example below keeps a running total of syscall
+ counts for the system during the run::
+
+ # echo 'hist:key=id.syscall:val=hitcount' > \
+ /sys/kernel/debug/tracing/events/raw_syscalls/sys_enter/trigger
+
+ # cat /sys/kernel/debug/tracing/events/raw_syscalls/sys_enter/hist
+ # trigger info: hist:keys=id.syscall:vals=hitcount:sort=hitcount:size=2048 [active]
+
+ { id: sys_fsync [ 74] } hitcount: 1
+ { id: sys_newuname [ 63] } hitcount: 1
+ { id: sys_prctl [157] } hitcount: 1
+ { id: sys_statfs [137] } hitcount: 1
+ { id: sys_symlink [ 88] } hitcount: 1
+ { id: sys_sendmmsg [307] } hitcount: 1
+ { id: sys_semctl [ 66] } hitcount: 1
+ { id: sys_readlink [ 89] } hitcount: 3
+ { id: sys_bind [ 49] } hitcount: 3
+ { id: sys_getsockname [ 51] } hitcount: 3
+ { id: sys_unlink [ 87] } hitcount: 3
+ { id: sys_rename [ 82] } hitcount: 4
+ { id: unknown_syscall [ 58] } hitcount: 4
+ { id: sys_connect [ 42] } hitcount: 4
+ { id: sys_getpid [ 39] } hitcount: 4
+ .
+ .
+ .
+ { id: sys_rt_sigprocmask [ 14] } hitcount: 952
+ { id: sys_futex [202] } hitcount: 1534
+ { id: sys_write [ 1] } hitcount: 2689
+ { id: sys_setitimer [ 38] } hitcount: 2797
+ { id: sys_read [ 0] } hitcount: 3202
+ { id: sys_select [ 23] } hitcount: 3773
+ { id: sys_writev [ 20] } hitcount: 4531
+ { id: sys_poll [ 7] } hitcount: 8314
+ { id: sys_recvmsg [ 47] } hitcount: 13738
+ { id: sys_ioctl [ 16] } hitcount: 21843
+
+ Totals:
+ Hits: 67612
+ Entries: 72
+ Dropped: 0
+
+ The syscall counts above provide a rough overall picture of system
+ call activity on the system; we can see for example that the most
+ popular system call on this system was the 'sys_ioctl' system call.
+
+ We can use 'compound' keys to refine that number and provide some
+ further insight as to which processes exactly contribute to the
+ overall ioctl count.
+
+ The command below keeps a hitcount for every unique combination of
+ system call id and pid - the end result is essentially a table
+ that keeps a per-pid sum of system call hits. The results are
+ sorted using the system call id as the primary key, and the
+ hitcount sum as the secondary key::
+
+ # echo 'hist:key=id.syscall,common_pid.execname:val=hitcount:sort=id,hitcount' > \
+ /sys/kernel/debug/tracing/events/raw_syscalls/sys_enter/trigger
+
+ # cat /sys/kernel/debug/tracing/events/raw_syscalls/sys_enter/hist
+ # trigger info: hist:keys=id.syscall,common_pid.execname:vals=hitcount:sort=id.syscall,hitcount:size=2048 [active]
+
+ { id: sys_read [ 0], common_pid: rtkit-daemon [ 1877] } hitcount: 1
+ { id: sys_read [ 0], common_pid: gdbus [ 2976] } hitcount: 1
+ { id: sys_read [ 0], common_pid: console-kit-dae [ 3400] } hitcount: 1
+ { id: sys_read [ 0], common_pid: postgres [ 1865] } hitcount: 1
+ { id: sys_read [ 0], common_pid: deja-dup-monito [ 3543] } hitcount: 2
+ { id: sys_read [ 0], common_pid: NetworkManager [ 890] } hitcount: 2
+ { id: sys_read [ 0], common_pid: evolution-calen [ 3048] } hitcount: 2
+ { id: sys_read [ 0], common_pid: postgres [ 1864] } hitcount: 2
+ { id: sys_read [ 0], common_pid: nm-applet [ 3022] } hitcount: 2
+ { id: sys_read [ 0], common_pid: whoopsie [ 1212] } hitcount: 2
+ .
+ .
+ .
+ { id: sys_ioctl [ 16], common_pid: bash [ 8479] } hitcount: 1
+ { id: sys_ioctl [ 16], common_pid: bash [ 3472] } hitcount: 12
+ { id: sys_ioctl [ 16], common_pid: gnome-terminal [ 3199] } hitcount: 16
+ { id: sys_ioctl [ 16], common_pid: Xorg [ 1267] } hitcount: 1808
+ { id: sys_ioctl [ 16], common_pid: compiz [ 2994] } hitcount: 5580
+ .
+ .
+ .
+ { id: sys_waitid [247], common_pid: upstart-dbus-br [ 2690] } hitcount: 3
+ { id: sys_waitid [247], common_pid: upstart-dbus-br [ 2688] } hitcount: 16
+ { id: sys_inotify_add_watch [254], common_pid: gmain [ 975] } hitcount: 2
+ { id: sys_inotify_add_watch [254], common_pid: gmain [ 3204] } hitcount: 4
+ { id: sys_inotify_add_watch [254], common_pid: gmain [ 2888] } hitcount: 4
+ { id: sys_inotify_add_watch [254], common_pid: gmain [ 3003] } hitcount: 4
+ { id: sys_inotify_add_watch [254], common_pid: gmain [ 2873] } hitcount: 4
+ { id: sys_inotify_add_watch [254], common_pid: gmain [ 3196] } hitcount: 6
+ { id: sys_openat [257], common_pid: java [ 2623] } hitcount: 2
+ { id: sys_eventfd2 [290], common_pid: ibus-ui-gtk3 [ 2760] } hitcount: 4
+ { id: sys_eventfd2 [290], common_pid: compiz [ 2994] } hitcount: 6
+
+ Totals:
+ Hits: 31536
+ Entries: 323
+ Dropped: 0
+
+ The above list does give us a breakdown of the ioctl syscall by
+ pid, but it also gives us quite a bit more than that, which we
+ don't really care about at the moment. Since we know the syscall
+ id for sys_ioctl (16, displayed next to the sys_ioctl name), we
+ can use that to filter out all the other syscalls::
+
+ # echo 'hist:key=id.syscall,common_pid.execname:val=hitcount:sort=id,hitcount if id == 16' > \
+ /sys/kernel/debug/tracing/events/raw_syscalls/sys_enter/trigger
+
+ # cat /sys/kernel/debug/tracing/events/raw_syscalls/sys_enter/hist
+ # trigger info: hist:keys=id.syscall,common_pid.execname:vals=hitcount:sort=id.syscall,hitcount:size=2048 if id == 16 [active]
+
+ { id: sys_ioctl [ 16], common_pid: gmain [ 2769] } hitcount: 1
+ { id: sys_ioctl [ 16], common_pid: evolution-addre [ 8571] } hitcount: 1
+ { id: sys_ioctl [ 16], common_pid: gmain [ 3003] } hitcount: 1
+ { id: sys_ioctl [ 16], common_pid: gmain [ 2781] } hitcount: 1
+ { id: sys_ioctl [ 16], common_pid: gmain [ 2829] } hitcount: 1
+ { id: sys_ioctl [ 16], common_pid: bash [ 8726] } hitcount: 1
+ { id: sys_ioctl [ 16], common_pid: bash [ 8508] } hitcount: 1
+ { id: sys_ioctl [ 16], common_pid: gmain [ 2970] } hitcount: 1
+ { id: sys_ioctl [ 16], common_pid: gmain [ 2768] } hitcount: 1
+ .
+ .
+ .
+ { id: sys_ioctl [ 16], common_pid: pool [ 8559] } hitcount: 45
+ { id: sys_ioctl [ 16], common_pid: pool [ 8555] } hitcount: 48
+ { id: sys_ioctl [ 16], common_pid: pool [ 8551] } hitcount: 48
+ { id: sys_ioctl [ 16], common_pid: avahi-daemon [ 896] } hitcount: 66
+ { id: sys_ioctl [ 16], common_pid: Xorg [ 1267] } hitcount: 26674
+ { id: sys_ioctl [ 16], common_pid: compiz [ 2994] } hitcount: 73443
+
+ Totals:
+ Hits: 101162
+ Entries: 103
+ Dropped: 0
+
+ The above output shows that 'compiz' and 'Xorg' are far and away
+ the heaviest ioctl callers (which might lead to questions about
+ whether they really need to be making all those calls and to
+ possible avenues for further investigation.)
+
+ The compound key examples used a key and a sum value (hitcount) to
+ sort the output, but we can just as easily use two keys instead.
+ Here's an example where we use a compound key composed of the the
+ common_pid and size event fields. Sorting with pid as the primary
+ key and 'size' as the secondary key allows us to display an
+ ordered summary of the recvfrom sizes, with counts, received by
+ each process::
+
+ # echo 'hist:key=common_pid.execname,size:val=hitcount:sort=common_pid,size' > \
+ /sys/kernel/debug/tracing/events/syscalls/sys_enter_recvfrom/trigger
+
+ # cat /sys/kernel/debug/tracing/events/syscalls/sys_enter_recvfrom/hist
+ # trigger info: hist:keys=common_pid.execname,size:vals=hitcount:sort=common_pid.execname,size:size=2048 [active]
+
+ { common_pid: smbd [ 784], size: 4 } hitcount: 1
+ { common_pid: dnsmasq [ 1412], size: 4096 } hitcount: 672
+ { common_pid: postgres [ 1796], size: 1000 } hitcount: 6
+ { common_pid: postgres [ 1867], size: 1000 } hitcount: 10
+ { common_pid: bamfdaemon [ 2787], size: 28 } hitcount: 2
+ { common_pid: bamfdaemon [ 2787], size: 14360 } hitcount: 1
+ { common_pid: compiz [ 2994], size: 8 } hitcount: 1
+ { common_pid: compiz [ 2994], size: 20 } hitcount: 11
+ { common_pid: gnome-terminal [ 3199], size: 4 } hitcount: 2
+ { common_pid: firefox [ 8817], size: 4 } hitcount: 1
+ { common_pid: firefox [ 8817], size: 8 } hitcount: 5
+ { common_pid: firefox [ 8817], size: 588 } hitcount: 2
+ { common_pid: firefox [ 8817], size: 628 } hitcount: 1
+ { common_pid: firefox [ 8817], size: 6944 } hitcount: 1
+ { common_pid: firefox [ 8817], size: 408880 } hitcount: 2
+ { common_pid: firefox [ 8822], size: 8 } hitcount: 2
+ { common_pid: firefox [ 8822], size: 160 } hitcount: 2
+ { common_pid: firefox [ 8822], size: 320 } hitcount: 2
+ { common_pid: firefox [ 8822], size: 352 } hitcount: 1
+ .
+ .
+ .
+ { common_pid: pool [ 8923], size: 1960 } hitcount: 10
+ { common_pid: pool [ 8923], size: 2048 } hitcount: 10
+ { common_pid: pool [ 8924], size: 1960 } hitcount: 10
+ { common_pid: pool [ 8924], size: 2048 } hitcount: 10
+ { common_pid: pool [ 8928], size: 1964 } hitcount: 4
+ { common_pid: pool [ 8928], size: 1965 } hitcount: 2
+ { common_pid: pool [ 8928], size: 2048 } hitcount: 6
+ { common_pid: pool [ 8929], size: 1982 } hitcount: 1
+ { common_pid: pool [ 8929], size: 2048 } hitcount: 1
+
+ Totals:
+ Hits: 2016
+ Entries: 224
+ Dropped: 0
+
+ The above example also illustrates the fact that although a compound
+ key is treated as a single entity for hashing purposes, the sub-keys
+ it's composed of can be accessed independently.
+
+ The next example uses a string field as the hash key and
+ demonstrates how you can manually pause and continue a hist trigger.
+ In this example, we'll aggregate fork counts and don't expect a
+ large number of entries in the hash table, so we'll drop it to a
+ much smaller number, say 256::
+
+ # echo 'hist:key=child_comm:val=hitcount:size=256' > \
+ /sys/kernel/debug/tracing/events/sched/sched_process_fork/trigger
+
+ # cat /sys/kernel/debug/tracing/events/sched/sched_process_fork/hist
+ # trigger info: hist:keys=child_comm:vals=hitcount:sort=hitcount:size=256 [active]
+
+ { child_comm: dconf worker } hitcount: 1
+ { child_comm: ibus-daemon } hitcount: 1
+ { child_comm: whoopsie } hitcount: 1
+ { child_comm: smbd } hitcount: 1
+ { child_comm: gdbus } hitcount: 1
+ { child_comm: kthreadd } hitcount: 1
+ { child_comm: dconf worker } hitcount: 1
+ { child_comm: evolution-alarm } hitcount: 2
+ { child_comm: Socket Thread } hitcount: 2
+ { child_comm: postgres } hitcount: 2
+ { child_comm: bash } hitcount: 3
+ { child_comm: compiz } hitcount: 3
+ { child_comm: evolution-sourc } hitcount: 4
+ { child_comm: dhclient } hitcount: 4
+ { child_comm: pool } hitcount: 5
+ { child_comm: nm-dispatcher.a } hitcount: 8
+ { child_comm: firefox } hitcount: 8
+ { child_comm: dbus-daemon } hitcount: 8
+ { child_comm: glib-pacrunner } hitcount: 10
+ { child_comm: evolution } hitcount: 23
+
+ Totals:
+ Hits: 89
+ Entries: 20
+ Dropped: 0
+
+ If we want to pause the hist trigger, we can simply append :pause to
+ the command that started the trigger. Notice that the trigger info
+ displays as [paused]::
+
+ # echo 'hist:key=child_comm:val=hitcount:size=256:pause' >> \
+ /sys/kernel/debug/tracing/events/sched/sched_process_fork/trigger
+
+ # cat /sys/kernel/debug/tracing/events/sched/sched_process_fork/hist
+ # trigger info: hist:keys=child_comm:vals=hitcount:sort=hitcount:size=256 [paused]
+
+ { child_comm: dconf worker } hitcount: 1
+ { child_comm: kthreadd } hitcount: 1
+ { child_comm: dconf worker } hitcount: 1
+ { child_comm: gdbus } hitcount: 1
+ { child_comm: ibus-daemon } hitcount: 1
+ { child_comm: Socket Thread } hitcount: 2
+ { child_comm: evolution-alarm } hitcount: 2
+ { child_comm: smbd } hitcount: 2
+ { child_comm: bash } hitcount: 3
+ { child_comm: whoopsie } hitcount: 3
+ { child_comm: compiz } hitcount: 3
+ { child_comm: evolution-sourc } hitcount: 4
+ { child_comm: pool } hitcount: 5
+ { child_comm: postgres } hitcount: 6
+ { child_comm: firefox } hitcount: 8
+ { child_comm: dhclient } hitcount: 10
+ { child_comm: emacs } hitcount: 12
+ { child_comm: dbus-daemon } hitcount: 20
+ { child_comm: nm-dispatcher.a } hitcount: 20
+ { child_comm: evolution } hitcount: 35
+ { child_comm: glib-pacrunner } hitcount: 59
+
+ Totals:
+ Hits: 199
+ Entries: 21
+ Dropped: 0
+
+ To manually continue having the trigger aggregate events, append
+ :cont instead. Notice that the trigger info displays as [active]
+ again, and the data has changed::
+
+ # echo 'hist:key=child_comm:val=hitcount:size=256:cont' >> \
+ /sys/kernel/debug/tracing/events/sched/sched_process_fork/trigger
+
+ # cat /sys/kernel/debug/tracing/events/sched/sched_process_fork/hist
+ # trigger info: hist:keys=child_comm:vals=hitcount:sort=hitcount:size=256 [active]
+
+ { child_comm: dconf worker } hitcount: 1
+ { child_comm: dconf worker } hitcount: 1
+ { child_comm: kthreadd } hitcount: 1
+ { child_comm: gdbus } hitcount: 1
+ { child_comm: ibus-daemon } hitcount: 1
+ { child_comm: Socket Thread } hitcount: 2
+ { child_comm: evolution-alarm } hitcount: 2
+ { child_comm: smbd } hitcount: 2
+ { child_comm: whoopsie } hitcount: 3
+ { child_comm: compiz } hitcount: 3
+ { child_comm: evolution-sourc } hitcount: 4
+ { child_comm: bash } hitcount: 5
+ { child_comm: pool } hitcount: 5
+ { child_comm: postgres } hitcount: 6
+ { child_comm: firefox } hitcount: 8
+ { child_comm: dhclient } hitcount: 11
+ { child_comm: emacs } hitcount: 12
+ { child_comm: dbus-daemon } hitcount: 22
+ { child_comm: nm-dispatcher.a } hitcount: 22
+ { child_comm: evolution } hitcount: 35
+ { child_comm: glib-pacrunner } hitcount: 59
+
+ Totals:
+ Hits: 206
+ Entries: 21
+ Dropped: 0
+
+ The previous example showed how to start and stop a hist trigger by
+ appending 'pause' and 'continue' to the hist trigger command. A
+ hist trigger can also be started in a paused state by initially
+ starting the trigger with ':pause' appended. This allows you to
+ start the trigger only when you're ready to start collecting data
+ and not before. For example, you could start the trigger in a
+ paused state, then unpause it and do something you want to measure,
+ then pause the trigger again when done.
+
+ Of course, doing this manually can be difficult and error-prone, but
+ it is possible to automatically start and stop a hist trigger based
+ on some condition, via the enable_hist and disable_hist triggers.
+
+ For example, suppose we wanted to take a look at the relative
+ weights in terms of skb length for each callpath that leads to a
+ netif_receieve_skb event when downloading a decent-sized file using
+ wget.
+
+ First we set up an initially paused stacktrace trigger on the
+ netif_receive_skb event::
+
+ # echo 'hist:key=stacktrace:vals=len:pause' > \
+ /sys/kernel/debug/tracing/events/net/netif_receive_skb/trigger
+
+ Next, we set up an 'enable_hist' trigger on the sched_process_exec
+ event, with an 'if filename==/usr/bin/wget' filter. The effect of
+ this new trigger is that it will 'unpause' the hist trigger we just
+ set up on netif_receive_skb if and only if it sees a
+ sched_process_exec event with a filename of '/usr/bin/wget'. When
+ that happens, all netif_receive_skb events are aggregated into a
+ hash table keyed on stacktrace::
+
+ # echo 'enable_hist:net:netif_receive_skb if filename==/usr/bin/wget' > \
+ /sys/kernel/debug/tracing/events/sched/sched_process_exec/trigger
+
+ The aggregation continues until the netif_receive_skb is paused
+ again, which is what the following disable_hist event does by
+ creating a similar setup on the sched_process_exit event, using the
+ filter 'comm==wget'::
+
+ # echo 'disable_hist:net:netif_receive_skb if comm==wget' > \
+ /sys/kernel/debug/tracing/events/sched/sched_process_exit/trigger
+
+ Whenever a process exits and the comm field of the disable_hist
+ trigger filter matches 'comm==wget', the netif_receive_skb hist
+ trigger is disabled.
+
+ The overall effect is that netif_receive_skb events are aggregated
+ into the hash table for only the duration of the wget. Executing a
+ wget command and then listing the 'hist' file will display the
+ output generated by the wget command::
+
+ $ wget https://www.kernel.org/pub/linux/kernel/v3.x/patch-3.19.xz
+
+ # cat /sys/kernel/debug/tracing/events/net/netif_receive_skb/hist
+ # trigger info: hist:keys=stacktrace:vals=len:sort=hitcount:size=2048 [paused]
+
+ { stacktrace:
+ __netif_receive_skb_core+0x46d/0x990
+ __netif_receive_skb+0x18/0x60
+ netif_receive_skb_internal+0x23/0x90
+ napi_gro_receive+0xc8/0x100
+ ieee80211_deliver_skb+0xd6/0x270 [mac80211]
+ ieee80211_rx_handlers+0xccf/0x22f0 [mac80211]
+ ieee80211_prepare_and_rx_handle+0x4e7/0xc40 [mac80211]
+ ieee80211_rx+0x31d/0x900 [mac80211]
+ iwlagn_rx_reply_rx+0x3db/0x6f0 [iwldvm]
+ iwl_rx_dispatch+0x8e/0xf0 [iwldvm]
+ iwl_pcie_irq_handler+0xe3c/0x12f0 [iwlwifi]
+ irq_thread_fn+0x20/0x50
+ irq_thread+0x11f/0x150
+ kthread+0xd2/0xf0
+ ret_from_fork+0x42/0x70
+ } hitcount: 85 len: 28884
+ { stacktrace:
+ __netif_receive_skb_core+0x46d/0x990
+ __netif_receive_skb+0x18/0x60
+ netif_receive_skb_internal+0x23/0x90
+ napi_gro_complete+0xa4/0xe0
+ dev_gro_receive+0x23a/0x360
+ napi_gro_receive+0x30/0x100
+ ieee80211_deliver_skb+0xd6/0x270 [mac80211]
+ ieee80211_rx_handlers+0xccf/0x22f0 [mac80211]
+ ieee80211_prepare_and_rx_handle+0x4e7/0xc40 [mac80211]
+ ieee80211_rx+0x31d/0x900 [mac80211]
+ iwlagn_rx_reply_rx+0x3db/0x6f0 [iwldvm]
+ iwl_rx_dispatch+0x8e/0xf0 [iwldvm]
+ iwl_pcie_irq_handler+0xe3c/0x12f0 [iwlwifi]
+ irq_thread_fn+0x20/0x50
+ irq_thread+0x11f/0x150
+ kthread+0xd2/0xf0
+ } hitcount: 98 len: 664329
+ { stacktrace:
+ __netif_receive_skb_core+0x46d/0x990
+ __netif_receive_skb+0x18/0x60
+ process_backlog+0xa8/0x150
+ net_rx_action+0x15d/0x340
+ __do_softirq+0x114/0x2c0
+ do_softirq_own_stack+0x1c/0x30
+ do_softirq+0x65/0x70
+ __local_bh_enable_ip+0xb5/0xc0
+ ip_finish_output+0x1f4/0x840
+ ip_output+0x6b/0xc0
+ ip_local_out_sk+0x31/0x40
+ ip_send_skb+0x1a/0x50
+ udp_send_skb+0x173/0x2a0
+ udp_sendmsg+0x2bf/0x9f0
+ inet_sendmsg+0x64/0xa0
+ sock_sendmsg+0x3d/0x50
+ } hitcount: 115 len: 13030
+ { stacktrace:
+ __netif_receive_skb_core+0x46d/0x990
+ __netif_receive_skb+0x18/0x60
+ netif_receive_skb_internal+0x23/0x90
+ napi_gro_complete+0xa4/0xe0
+ napi_gro_flush+0x6d/0x90
+ iwl_pcie_irq_handler+0x92a/0x12f0 [iwlwifi]
+ irq_thread_fn+0x20/0x50
+ irq_thread+0x11f/0x150
+ kthread+0xd2/0xf0
+ ret_from_fork+0x42/0x70
+ } hitcount: 934 len: 5512212
+
+ Totals:
+ Hits: 1232
+ Entries: 4
+ Dropped: 0
+
+ The above shows all the netif_receive_skb callpaths and their total
+ lengths for the duration of the wget command.
+
+ The 'clear' hist trigger param can be used to clear the hash table.
+ Suppose we wanted to try another run of the previous example but
+ this time also wanted to see the complete list of events that went
+ into the histogram. In order to avoid having to set everything up
+ again, we can just clear the histogram first::
+
+ # echo 'hist:key=stacktrace:vals=len:clear' >> \
+ /sys/kernel/debug/tracing/events/net/netif_receive_skb/trigger
+
+ Just to verify that it is in fact cleared, here's what we now see in
+ the hist file::
+
+ # cat /sys/kernel/debug/tracing/events/net/netif_receive_skb/hist
+ # trigger info: hist:keys=stacktrace:vals=len:sort=hitcount:size=2048 [paused]
+
+ Totals:
+ Hits: 0
+ Entries: 0
+ Dropped: 0
+
+ Since we want to see the detailed list of every netif_receive_skb
+ event occurring during the new run, which are in fact the same
+ events being aggregated into the hash table, we add some additional
+ 'enable_event' events to the triggering sched_process_exec and
+ sched_process_exit events as such::
+
+ # echo 'enable_event:net:netif_receive_skb if filename==/usr/bin/wget' > \
+ /sys/kernel/debug/tracing/events/sched/sched_process_exec/trigger
+
+ # echo 'disable_event:net:netif_receive_skb if comm==wget' > \
+ /sys/kernel/debug/tracing/events/sched/sched_process_exit/trigger
+
+ If you read the trigger files for the sched_process_exec and
+ sched_process_exit triggers, you should see two triggers for each:
+ one enabling/disabling the hist aggregation and the other
+ enabling/disabling the logging of events::
+
+ # cat /sys/kernel/debug/tracing/events/sched/sched_process_exec/trigger
+ enable_event:net:netif_receive_skb:unlimited if filename==/usr/bin/wget
+ enable_hist:net:netif_receive_skb:unlimited if filename==/usr/bin/wget
+
+ # cat /sys/kernel/debug/tracing/events/sched/sched_process_exit/trigger
+ enable_event:net:netif_receive_skb:unlimited if comm==wget
+ disable_hist:net:netif_receive_skb:unlimited if comm==wget
+
+ In other words, whenever either of the sched_process_exec or
+ sched_process_exit events is hit and matches 'wget', it enables or
+ disables both the histogram and the event log, and what you end up
+ with is a hash table and set of events just covering the specified
+ duration. Run the wget command again::
+
+ $ wget https://www.kernel.org/pub/linux/kernel/v3.x/patch-3.19.xz
+
+ Displaying the 'hist' file should show something similar to what you
+ saw in the last run, but this time you should also see the
+ individual events in the trace file::
+
+ # cat /sys/kernel/debug/tracing/trace
+
+ # tracer: nop
+ #
+ # entries-in-buffer/entries-written: 183/1426 #P:4
+ #
+ # _-----=> irqs-off
+ # / _----=> need-resched
+ # | / _---=> hardirq/softirq
+ # || / _--=> preempt-depth
+ # ||| / delay
+ # TASK-PID CPU# |||| TIMESTAMP FUNCTION
+ # | | | |||| | |
+ wget-15108 [000] ..s1 31769.606929: netif_receive_skb: dev=lo skbaddr=ffff88009c353100 len=60
+ wget-15108 [000] ..s1 31769.606999: netif_receive_skb: dev=lo skbaddr=ffff88009c353200 len=60
+ dnsmasq-1382 [000] ..s1 31769.677652: netif_receive_skb: dev=lo skbaddr=ffff88009c352b00 len=130
+ dnsmasq-1382 [000] ..s1 31769.685917: netif_receive_skb: dev=lo skbaddr=ffff88009c352200 len=138
+ ##### CPU 2 buffer started ####
+ irq/29-iwlwifi-559 [002] ..s. 31772.031529: netif_receive_skb: dev=wlan0 skbaddr=ffff88009d433d00 len=2948
+ irq/29-iwlwifi-559 [002] ..s. 31772.031572: netif_receive_skb: dev=wlan0 skbaddr=ffff88009d432200 len=1500
+ irq/29-iwlwifi-559 [002] ..s. 31772.032196: netif_receive_skb: dev=wlan0 skbaddr=ffff88009d433100 len=2948
+ irq/29-iwlwifi-559 [002] ..s. 31772.032761: netif_receive_skb: dev=wlan0 skbaddr=ffff88009d433000 len=2948
+ irq/29-iwlwifi-559 [002] ..s. 31772.033220: netif_receive_skb: dev=wlan0 skbaddr=ffff88009d432e00 len=1500
+ ....
+
+
+ The following example demonstrates how multiple hist triggers can be
+ attached to a given event. This capability can be useful for
+ creating a set of different summaries derived from the same set of
+ events, or for comparing the effects of different filters, among
+ other things.
+ ::
+
+ # echo 'hist:keys=skbaddr.hex:vals=len if len < 0' >> \
+ /sys/kernel/debug/tracing/events/net/netif_receive_skb/trigger
+ # echo 'hist:keys=skbaddr.hex:vals=len if len > 4096' >> \
+ /sys/kernel/debug/tracing/events/net/netif_receive_skb/trigger
+ # echo 'hist:keys=skbaddr.hex:vals=len if len == 256' >> \
+ /sys/kernel/debug/tracing/events/net/netif_receive_skb/trigger
+ # echo 'hist:keys=skbaddr.hex:vals=len' >> \
+ /sys/kernel/debug/tracing/events/net/netif_receive_skb/trigger
+ # echo 'hist:keys=len:vals=common_preempt_count' >> \
+ /sys/kernel/debug/tracing/events/net/netif_receive_skb/trigger
+
+ The above set of commands create four triggers differing only in
+ their filters, along with a completely different though fairly
+ nonsensical trigger. Note that in order to append multiple hist
+ triggers to the same file, you should use the '>>' operator to
+ append them ('>' will also add the new hist trigger, but will remove
+ any existing hist triggers beforehand).
+
+ Displaying the contents of the 'hist' file for the event shows the
+ contents of all five histograms::
+
+ # cat /sys/kernel/debug/tracing/events/net/netif_receive_skb/hist
+
+ # event histogram
+ #
+ # trigger info: hist:keys=len:vals=hitcount,common_preempt_count:sort=hitcount:size=2048 [active]
+ #
+
+ { len: 176 } hitcount: 1 common_preempt_count: 0
+ { len: 223 } hitcount: 1 common_preempt_count: 0
+ { len: 4854 } hitcount: 1 common_preempt_count: 0
+ { len: 395 } hitcount: 1 common_preempt_count: 0
+ { len: 177 } hitcount: 1 common_preempt_count: 0
+ { len: 446 } hitcount: 1 common_preempt_count: 0
+ { len: 1601 } hitcount: 1 common_preempt_count: 0
+ .
+ .
+ .
+ { len: 1280 } hitcount: 66 common_preempt_count: 0
+ { len: 116 } hitcount: 81 common_preempt_count: 40
+ { len: 708 } hitcount: 112 common_preempt_count: 0
+ { len: 46 } hitcount: 221 common_preempt_count: 0
+ { len: 1264 } hitcount: 458 common_preempt_count: 0
+
+ Totals:
+ Hits: 1428
+ Entries: 147
+ Dropped: 0
+
+
+ # event histogram
+ #
+ # trigger info: hist:keys=skbaddr.hex:vals=hitcount,len:sort=hitcount:size=2048 [active]
+ #
+
+ { skbaddr: ffff8800baee5e00 } hitcount: 1 len: 130
+ { skbaddr: ffff88005f3d5600 } hitcount: 1 len: 1280
+ { skbaddr: ffff88005f3d4900 } hitcount: 1 len: 1280
+ { skbaddr: ffff88009fed6300 } hitcount: 1 len: 115
+ { skbaddr: ffff88009fe0ad00 } hitcount: 1 len: 115
+ { skbaddr: ffff88008cdb1900 } hitcount: 1 len: 46
+ { skbaddr: ffff880064b5ef00 } hitcount: 1 len: 118
+ { skbaddr: ffff880044e3c700 } hitcount: 1 len: 60
+ { skbaddr: ffff880100065900 } hitcount: 1 len: 46
+ { skbaddr: ffff8800d46bd500 } hitcount: 1 len: 116
+ { skbaddr: ffff88005f3d5f00 } hitcount: 1 len: 1280
+ { skbaddr: ffff880100064700 } hitcount: 1 len: 365
+ { skbaddr: ffff8800badb6f00 } hitcount: 1 len: 60
+ .
+ .
+ .
+ { skbaddr: ffff88009fe0be00 } hitcount: 27 len: 24677
+ { skbaddr: ffff88009fe0a400 } hitcount: 27 len: 23052
+ { skbaddr: ffff88009fe0b700 } hitcount: 31 len: 25589
+ { skbaddr: ffff88009fe0b600 } hitcount: 32 len: 27326
+ { skbaddr: ffff88006a462800 } hitcount: 68 len: 71678
+ { skbaddr: ffff88006a463700 } hitcount: 70 len: 72678
+ { skbaddr: ffff88006a462b00 } hitcount: 71 len: 77589
+ { skbaddr: ffff88006a463600 } hitcount: 73 len: 71307
+ { skbaddr: ffff88006a462200 } hitcount: 81 len: 81032
+
+ Totals:
+ Hits: 1451
+ Entries: 318
+ Dropped: 0
+
+
+ # event histogram
+ #
+ # trigger info: hist:keys=skbaddr.hex:vals=hitcount,len:sort=hitcount:size=2048 if len == 256 [active]
+ #
+
+
+ Totals:
+ Hits: 0
+ Entries: 0
+ Dropped: 0
+
+
+ # event histogram
+ #
+ # trigger info: hist:keys=skbaddr.hex:vals=hitcount,len:sort=hitcount:size=2048 if len > 4096 [active]
+ #
+
+ { skbaddr: ffff88009fd2c300 } hitcount: 1 len: 7212
+ { skbaddr: ffff8800d2bcce00 } hitcount: 1 len: 7212
+ { skbaddr: ffff8800d2bcd700 } hitcount: 1 len: 7212
+ { skbaddr: ffff8800d2bcda00 } hitcount: 1 len: 21492
+ { skbaddr: ffff8800ae2e2d00 } hitcount: 1 len: 7212
+ { skbaddr: ffff8800d2bcdb00 } hitcount: 1 len: 7212
+ { skbaddr: ffff88006a4df500 } hitcount: 1 len: 4854
+ { skbaddr: ffff88008ce47b00 } hitcount: 1 len: 18636
+ { skbaddr: ffff8800ae2e2200 } hitcount: 1 len: 12924
+ { skbaddr: ffff88005f3e1000 } hitcount: 1 len: 4356
+ { skbaddr: ffff8800d2bcdc00 } hitcount: 2 len: 24420
+ { skbaddr: ffff8800d2bcc200 } hitcount: 2 len: 12996
+
+ Totals:
+ Hits: 14
+ Entries: 12
+ Dropped: 0
+
+
+ # event histogram
+ #
+ # trigger info: hist:keys=skbaddr.hex:vals=hitcount,len:sort=hitcount:size=2048 if len < 0 [active]
+ #
+
+
+ Totals:
+ Hits: 0
+ Entries: 0
+ Dropped: 0
+
+ Named triggers can be used to have triggers share a common set of
+ histogram data. This capability is mostly useful for combining the
+ output of events generated by tracepoints contained inside inline
+ functions, but names can be used in a hist trigger on any event.
+ For example, these two triggers when hit will update the same 'len'
+ field in the shared 'foo' histogram data::
+
+ # echo 'hist:name=foo:keys=skbaddr.hex:vals=len' > \
+ /sys/kernel/debug/tracing/events/net/netif_receive_skb/trigger
+ # echo 'hist:name=foo:keys=skbaddr.hex:vals=len' > \
+ /sys/kernel/debug/tracing/events/net/netif_rx/trigger
+
+ You can see that they're updating common histogram data by reading
+ each event's hist files at the same time::
+
+ # cat /sys/kernel/debug/tracing/events/net/netif_receive_skb/hist;
+ cat /sys/kernel/debug/tracing/events/net/netif_rx/hist
+
+ # event histogram
+ #
+ # trigger info: hist:name=foo:keys=skbaddr.hex:vals=hitcount,len:sort=hitcount:size=2048 [active]
+ #
+
+ { skbaddr: ffff88000ad53500 } hitcount: 1 len: 46
+ { skbaddr: ffff8800af5a1500 } hitcount: 1 len: 76
+ { skbaddr: ffff8800d62a1900 } hitcount: 1 len: 46
+ { skbaddr: ffff8800d2bccb00 } hitcount: 1 len: 468
+ { skbaddr: ffff8800d3c69900 } hitcount: 1 len: 46
+ { skbaddr: ffff88009ff09100 } hitcount: 1 len: 52
+ { skbaddr: ffff88010f13ab00 } hitcount: 1 len: 168
+ { skbaddr: ffff88006a54f400 } hitcount: 1 len: 46
+ { skbaddr: ffff8800d2bcc500 } hitcount: 1 len: 260
+ { skbaddr: ffff880064505000 } hitcount: 1 len: 46
+ { skbaddr: ffff8800baf24e00 } hitcount: 1 len: 32
+ { skbaddr: ffff88009fe0ad00 } hitcount: 1 len: 46
+ { skbaddr: ffff8800d3edff00 } hitcount: 1 len: 44
+ { skbaddr: ffff88009fe0b400 } hitcount: 1 len: 168
+ { skbaddr: ffff8800a1c55a00 } hitcount: 1 len: 40
+ { skbaddr: ffff8800d2bcd100 } hitcount: 1 len: 40
+ { skbaddr: ffff880064505f00 } hitcount: 1 len: 174
+ { skbaddr: ffff8800a8bff200 } hitcount: 1 len: 160
+ { skbaddr: ffff880044e3cc00 } hitcount: 1 len: 76
+ { skbaddr: ffff8800a8bfe700 } hitcount: 1 len: 46
+ { skbaddr: ffff8800d2bcdc00 } hitcount: 1 len: 32
+ { skbaddr: ffff8800a1f64800 } hitcount: 1 len: 46
+ { skbaddr: ffff8800d2bcde00 } hitcount: 1 len: 988
+ { skbaddr: ffff88006a5dea00 } hitcount: 1 len: 46
+ { skbaddr: ffff88002e37a200 } hitcount: 1 len: 44
+ { skbaddr: ffff8800a1f32c00 } hitcount: 2 len: 676
+ { skbaddr: ffff88000ad52600 } hitcount: 2 len: 107
+ { skbaddr: ffff8800a1f91e00 } hitcount: 2 len: 92
+ { skbaddr: ffff8800af5a0200 } hitcount: 2 len: 142
+ { skbaddr: ffff8800d2bcc600 } hitcount: 2 len: 220
+ { skbaddr: ffff8800ba36f500 } hitcount: 2 len: 92
+ { skbaddr: ffff8800d021f800 } hitcount: 2 len: 92
+ { skbaddr: ffff8800a1f33600 } hitcount: 2 len: 675
+ { skbaddr: ffff8800a8bfff00 } hitcount: 3 len: 138
+ { skbaddr: ffff8800d62a1300 } hitcount: 3 len: 138
+ { skbaddr: ffff88002e37a100 } hitcount: 4 len: 184
+ { skbaddr: ffff880064504400 } hitcount: 4 len: 184
+ { skbaddr: ffff8800a8bfec00 } hitcount: 4 len: 184
+ { skbaddr: ffff88000ad53700 } hitcount: 5 len: 230
+ { skbaddr: ffff8800d2bcdb00 } hitcount: 5 len: 196
+ { skbaddr: ffff8800a1f90000 } hitcount: 6 len: 276
+ { skbaddr: ffff88006a54f900 } hitcount: 6 len: 276
+
+ Totals:
+ Hits: 81
+ Entries: 42
+ Dropped: 0
+ # event histogram
+ #
+ # trigger info: hist:name=foo:keys=skbaddr.hex:vals=hitcount,len:sort=hitcount:size=2048 [active]
+ #
+
+ { skbaddr: ffff88000ad53500 } hitcount: 1 len: 46
+ { skbaddr: ffff8800af5a1500 } hitcount: 1 len: 76
+ { skbaddr: ffff8800d62a1900 } hitcount: 1 len: 46
+ { skbaddr: ffff8800d2bccb00 } hitcount: 1 len: 468
+ { skbaddr: ffff8800d3c69900 } hitcount: 1 len: 46
+ { skbaddr: ffff88009ff09100 } hitcount: 1 len: 52
+ { skbaddr: ffff88010f13ab00 } hitcount: 1 len: 168
+ { skbaddr: ffff88006a54f400 } hitcount: 1 len: 46
+ { skbaddr: ffff8800d2bcc500 } hitcount: 1 len: 260
+ { skbaddr: ffff880064505000 } hitcount: 1 len: 46
+ { skbaddr: ffff8800baf24e00 } hitcount: 1 len: 32
+ { skbaddr: ffff88009fe0ad00 } hitcount: 1 len: 46
+ { skbaddr: ffff8800d3edff00 } hitcount: 1 len: 44
+ { skbaddr: ffff88009fe0b400 } hitcount: 1 len: 168
+ { skbaddr: ffff8800a1c55a00 } hitcount: 1 len: 40
+ { skbaddr: ffff8800d2bcd100 } hitcount: 1 len: 40
+ { skbaddr: ffff880064505f00 } hitcount: 1 len: 174
+ { skbaddr: ffff8800a8bff200 } hitcount: 1 len: 160
+ { skbaddr: ffff880044e3cc00 } hitcount: 1 len: 76
+ { skbaddr: ffff8800a8bfe700 } hitcount: 1 len: 46
+ { skbaddr: ffff8800d2bcdc00 } hitcount: 1 len: 32
+ { skbaddr: ffff8800a1f64800 } hitcount: 1 len: 46
+ { skbaddr: ffff8800d2bcde00 } hitcount: 1 len: 988
+ { skbaddr: ffff88006a5dea00 } hitcount: 1 len: 46
+ { skbaddr: ffff88002e37a200 } hitcount: 1 len: 44
+ { skbaddr: ffff8800a1f32c00 } hitcount: 2 len: 676
+ { skbaddr: ffff88000ad52600 } hitcount: 2 len: 107
+ { skbaddr: ffff8800a1f91e00 } hitcount: 2 len: 92
+ { skbaddr: ffff8800af5a0200 } hitcount: 2 len: 142
+ { skbaddr: ffff8800d2bcc600 } hitcount: 2 len: 220
+ { skbaddr: ffff8800ba36f500 } hitcount: 2 len: 92
+ { skbaddr: ffff8800d021f800 } hitcount: 2 len: 92
+ { skbaddr: ffff8800a1f33600 } hitcount: 2 len: 675
+ { skbaddr: ffff8800a8bfff00 } hitcount: 3 len: 138
+ { skbaddr: ffff8800d62a1300 } hitcount: 3 len: 138
+ { skbaddr: ffff88002e37a100 } hitcount: 4 len: 184
+ { skbaddr: ffff880064504400 } hitcount: 4 len: 184
+ { skbaddr: ffff8800a8bfec00 } hitcount: 4 len: 184
+ { skbaddr: ffff88000ad53700 } hitcount: 5 len: 230
+ { skbaddr: ffff8800d2bcdb00 } hitcount: 5 len: 196
+ { skbaddr: ffff8800a1f90000 } hitcount: 6 len: 276
+ { skbaddr: ffff88006a54f900 } hitcount: 6 len: 276
+
+ Totals:
+ Hits: 81
+ Entries: 42
+ Dropped: 0
+
+ And here's an example that shows how to combine histogram data from
+ any two events even if they don't share any 'compatible' fields
+ other than 'hitcount' and 'stacktrace'. These commands create a
+ couple of triggers named 'bar' using those fields::
+
+ # echo 'hist:name=bar:key=stacktrace:val=hitcount' > \
+ /sys/kernel/debug/tracing/events/sched/sched_process_fork/trigger
+ # echo 'hist:name=bar:key=stacktrace:val=hitcount' > \
+ /sys/kernel/debug/tracing/events/net/netif_rx/trigger
+
+ And displaying the output of either shows some interesting if
+ somewhat confusing output::
+
+ # cat /sys/kernel/debug/tracing/events/sched/sched_process_fork/hist
+ # cat /sys/kernel/debug/tracing/events/net/netif_rx/hist
+
+ # event histogram
+ #
+ # trigger info: hist:name=bar:keys=stacktrace:vals=hitcount:sort=hitcount:size=2048 [active]
+ #
+
+ { stacktrace:
+ _do_fork+0x18e/0x330
+ kernel_thread+0x29/0x30
+ kthreadd+0x154/0x1b0
+ ret_from_fork+0x3f/0x70
+ } hitcount: 1
+ { stacktrace:
+ netif_rx_internal+0xb2/0xd0
+ netif_rx_ni+0x20/0x70
+ dev_loopback_xmit+0xaa/0xd0
+ ip_mc_output+0x126/0x240
+ ip_local_out_sk+0x31/0x40
+ igmp_send_report+0x1e9/0x230
+ igmp_timer_expire+0xe9/0x120
+ call_timer_fn+0x39/0xf0
+ run_timer_softirq+0x1e1/0x290
+ __do_softirq+0xfd/0x290
+ irq_exit+0x98/0xb0
+ smp_apic_timer_interrupt+0x4a/0x60
+ apic_timer_interrupt+0x6d/0x80
+ cpuidle_enter+0x17/0x20
+ call_cpuidle+0x3b/0x60
+ cpu_startup_entry+0x22d/0x310
+ } hitcount: 1
+ { stacktrace:
+ netif_rx_internal+0xb2/0xd0
+ netif_rx_ni+0x20/0x70
+ dev_loopback_xmit+0xaa/0xd0
+ ip_mc_output+0x17f/0x240
+ ip_local_out_sk+0x31/0x40
+ ip_send_skb+0x1a/0x50
+ udp_send_skb+0x13e/0x270
+ udp_sendmsg+0x2bf/0x980
+ inet_sendmsg+0x67/0xa0
+ sock_sendmsg+0x38/0x50
+ SYSC_sendto+0xef/0x170
+ SyS_sendto+0xe/0x10
+ entry_SYSCALL_64_fastpath+0x12/0x6a
+ } hitcount: 2
+ { stacktrace:
+ netif_rx_internal+0xb2/0xd0
+ netif_rx+0x1c/0x60
+ loopback_xmit+0x6c/0xb0
+ dev_hard_start_xmit+0x219/0x3a0
+ __dev_queue_xmit+0x415/0x4f0
+ dev_queue_xmit_sk+0x13/0x20
+ ip_finish_output2+0x237/0x340
+ ip_finish_output+0x113/0x1d0
+ ip_output+0x66/0xc0
+ ip_local_out_sk+0x31/0x40
+ ip_send_skb+0x1a/0x50
+ udp_send_skb+0x16d/0x270
+ udp_sendmsg+0x2bf/0x980
+ inet_sendmsg+0x67/0xa0
+ sock_sendmsg+0x38/0x50
+ ___sys_sendmsg+0x14e/0x270
+ } hitcount: 76
+ { stacktrace:
+ netif_rx_internal+0xb2/0xd0
+ netif_rx+0x1c/0x60
+ loopback_xmit+0x6c/0xb0
+ dev_hard_start_xmit+0x219/0x3a0
+ __dev_queue_xmit+0x415/0x4f0
+ dev_queue_xmit_sk+0x13/0x20
+ ip_finish_output2+0x237/0x340
+ ip_finish_output+0x113/0x1d0
+ ip_output+0x66/0xc0
+ ip_local_out_sk+0x31/0x40
+ ip_send_skb+0x1a/0x50
+ udp_send_skb+0x16d/0x270
+ udp_sendmsg+0x2bf/0x980
+ inet_sendmsg+0x67/0xa0
+ sock_sendmsg+0x38/0x50
+ ___sys_sendmsg+0x269/0x270
+ } hitcount: 77
+ { stacktrace:
+ netif_rx_internal+0xb2/0xd0
+ netif_rx+0x1c/0x60
+ loopback_xmit+0x6c/0xb0
+ dev_hard_start_xmit+0x219/0x3a0
+ __dev_queue_xmit+0x415/0x4f0
+ dev_queue_xmit_sk+0x13/0x20
+ ip_finish_output2+0x237/0x340
+ ip_finish_output+0x113/0x1d0
+ ip_output+0x66/0xc0
+ ip_local_out_sk+0x31/0x40
+ ip_send_skb+0x1a/0x50
+ udp_send_skb+0x16d/0x270
+ udp_sendmsg+0x2bf/0x980
+ inet_sendmsg+0x67/0xa0
+ sock_sendmsg+0x38/0x50
+ SYSC_sendto+0xef/0x170
+ } hitcount: 88
+ { stacktrace:
+ _do_fork+0x18e/0x330
+ SyS_clone+0x19/0x20
+ entry_SYSCALL_64_fastpath+0x12/0x6a
+ } hitcount: 244
+
+ Totals:
+ Hits: 489
+ Entries: 7
+ Dropped: 0
+++ /dev/null
- Event Tracing
-
- Documentation written by Theodore Ts'o
- Updated by Li Zefan and Tom Zanussi
-
-1. Introduction
-===============
-
-Tracepoints (see Documentation/trace/tracepoints.txt) can be used
-without creating custom kernel modules to register probe functions
-using the event tracing infrastructure.
-
-Not all tracepoints can be traced using the event tracing system;
-the kernel developer must provide code snippets which define how the
-tracing information is saved into the tracing buffer, and how the
-tracing information should be printed.
-
-2. Using Event Tracing
-======================
-
-2.1 Via the 'set_event' interface
----------------------------------
-
-The events which are available for tracing can be found in the file
-/sys/kernel/debug/tracing/available_events.
-
-To enable a particular event, such as 'sched_wakeup', simply echo it
-to /sys/kernel/debug/tracing/set_event. For example:
-
- # echo sched_wakeup >> /sys/kernel/debug/tracing/set_event
-
-[ Note: '>>' is necessary, otherwise it will firstly disable
- all the events. ]
-
-To disable an event, echo the event name to the set_event file prefixed
-with an exclamation point:
-
- # echo '!sched_wakeup' >> /sys/kernel/debug/tracing/set_event
-
-To disable all events, echo an empty line to the set_event file:
-
- # echo > /sys/kernel/debug/tracing/set_event
-
-To enable all events, echo '*:*' or '*:' to the set_event file:
-
- # echo *:* > /sys/kernel/debug/tracing/set_event
-
-The events are organized into subsystems, such as ext4, irq, sched,
-etc., and a full event name looks like this: <subsystem>:<event>. The
-subsystem name is optional, but it is displayed in the available_events
-file. All of the events in a subsystem can be specified via the syntax
-"<subsystem>:*"; for example, to enable all irq events, you can use the
-command:
-
- # echo 'irq:*' > /sys/kernel/debug/tracing/set_event
-
-2.2 Via the 'enable' toggle
----------------------------
-
-The events available are also listed in /sys/kernel/debug/tracing/events/ hierarchy
-of directories.
-
-To enable event 'sched_wakeup':
-
- # echo 1 > /sys/kernel/debug/tracing/events/sched/sched_wakeup/enable
-
-To disable it:
-
- # echo 0 > /sys/kernel/debug/tracing/events/sched/sched_wakeup/enable
-
-To enable all events in sched subsystem:
-
- # echo 1 > /sys/kernel/debug/tracing/events/sched/enable
-
-To enable all events:
-
- # echo 1 > /sys/kernel/debug/tracing/events/enable
-
-When reading one of these enable files, there are four results:
-
- 0 - all events this file affects are disabled
- 1 - all events this file affects are enabled
- X - there is a mixture of events enabled and disabled
- ? - this file does not affect any event
-
-2.3 Boot option
----------------
-
-In order to facilitate early boot debugging, use boot option:
-
- trace_event=[event-list]
-
-event-list is a comma separated list of events. See section 2.1 for event
-format.
-
-3. Defining an event-enabled tracepoint
-=======================================
-
-See The example provided in samples/trace_events
-
-4. Event formats
-================
-
-Each trace event has a 'format' file associated with it that contains
-a description of each field in a logged event. This information can
-be used to parse the binary trace stream, and is also the place to
-find the field names that can be used in event filters (see section 5).
-
-It also displays the format string that will be used to print the
-event in text mode, along with the event name and ID used for
-profiling.
-
-Every event has a set of 'common' fields associated with it; these are
-the fields prefixed with 'common_'. The other fields vary between
-events and correspond to the fields defined in the TRACE_EVENT
-definition for that event.
-
-Each field in the format has the form:
-
- field:field-type field-name; offset:N; size:N;
-
-where offset is the offset of the field in the trace record and size
-is the size of the data item, in bytes.
-
-For example, here's the information displayed for the 'sched_wakeup'
-event:
-
-# cat /sys/kernel/debug/tracing/events/sched/sched_wakeup/format
-
-name: sched_wakeup
-ID: 60
-format:
- field:unsigned short common_type; offset:0; size:2;
- field:unsigned char common_flags; offset:2; size:1;
- field:unsigned char common_preempt_count; offset:3; size:1;
- field:int common_pid; offset:4; size:4;
- field:int common_tgid; offset:8; size:4;
-
- field:char comm[TASK_COMM_LEN]; offset:12; size:16;
- field:pid_t pid; offset:28; size:4;
- field:int prio; offset:32; size:4;
- field:int success; offset:36; size:4;
- field:int cpu; offset:40; size:4;
-
-print fmt: "task %s:%d [%d] success=%d [%03d]", REC->comm, REC->pid,
- REC->prio, REC->success, REC->cpu
-
-This event contains 10 fields, the first 5 common and the remaining 5
-event-specific. All the fields for this event are numeric, except for
-'comm' which is a string, a distinction important for event filtering.
-
-5. Event filtering
-==================
-
-Trace events can be filtered in the kernel by associating boolean
-'filter expressions' with them. As soon as an event is logged into
-the trace buffer, its fields are checked against the filter expression
-associated with that event type. An event with field values that
-'match' the filter will appear in the trace output, and an event whose
-values don't match will be discarded. An event with no filter
-associated with it matches everything, and is the default when no
-filter has been set for an event.
-
-5.1 Expression syntax
----------------------
-
-A filter expression consists of one or more 'predicates' that can be
-combined using the logical operators '&&' and '||'. A predicate is
-simply a clause that compares the value of a field contained within a
-logged event with a constant value and returns either 0 or 1 depending
-on whether the field value matched (1) or didn't match (0):
-
- field-name relational-operator value
-
-Parentheses can be used to provide arbitrary logical groupings and
-double-quotes can be used to prevent the shell from interpreting
-operators as shell metacharacters.
-
-The field-names available for use in filters can be found in the
-'format' files for trace events (see section 4).
-
-The relational-operators depend on the type of the field being tested:
-
-The operators available for numeric fields are:
-
-==, !=, <, <=, >, >=, &
-
-And for string fields they are:
-
-==, !=, ~
-
-The glob (~) accepts a wild card character (*,?) and character classes
-([). For example:
-
- prev_comm ~ "*sh"
- prev_comm ~ "sh*"
- prev_comm ~ "*sh*"
- prev_comm ~ "ba*sh"
-
-5.2 Setting filters
--------------------
-
-A filter for an individual event is set by writing a filter expression
-to the 'filter' file for the given event.
-
-For example:
-
-# cd /sys/kernel/debug/tracing/events/sched/sched_wakeup
-# echo "common_preempt_count > 4" > filter
-
-A slightly more involved example:
-
-# cd /sys/kernel/debug/tracing/events/signal/signal_generate
-# echo "((sig >= 10 && sig < 15) || sig == 17) && comm != bash" > filter
-
-If there is an error in the expression, you'll get an 'Invalid
-argument' error when setting it, and the erroneous string along with
-an error message can be seen by looking at the filter e.g.:
-
-# cd /sys/kernel/debug/tracing/events/signal/signal_generate
-# echo "((sig >= 10 && sig < 15) || dsig == 17) && comm != bash" > filter
--bash: echo: write error: Invalid argument
-# cat filter
-((sig >= 10 && sig < 15) || dsig == 17) && comm != bash
-^
-parse_error: Field not found
-
-Currently the caret ('^') for an error always appears at the beginning of
-the filter string; the error message should still be useful though
-even without more accurate position info.
-
-5.3 Clearing filters
---------------------
-
-To clear the filter for an event, write a '0' to the event's filter
-file.
-
-To clear the filters for all events in a subsystem, write a '0' to the
-subsystem's filter file.
-
-5.3 Subsystem filters
----------------------
-
-For convenience, filters for every event in a subsystem can be set or
-cleared as a group by writing a filter expression into the filter file
-at the root of the subsystem. Note however, that if a filter for any
-event within the subsystem lacks a field specified in the subsystem
-filter, or if the filter can't be applied for any other reason, the
-filter for that event will retain its previous setting. This can
-result in an unintended mixture of filters which could lead to
-confusing (to the user who might think different filters are in
-effect) trace output. Only filters that reference just the common
-fields can be guaranteed to propagate successfully to all events.
-
-Here are a few subsystem filter examples that also illustrate the
-above points:
-
-Clear the filters on all events in the sched subsystem:
-
-# cd /sys/kernel/debug/tracing/events/sched
-# echo 0 > filter
-# cat sched_switch/filter
-none
-# cat sched_wakeup/filter
-none
-
-Set a filter using only common fields for all events in the sched
-subsystem (all events end up with the same filter):
-
-# cd /sys/kernel/debug/tracing/events/sched
-# echo common_pid == 0 > filter
-# cat sched_switch/filter
-common_pid == 0
-# cat sched_wakeup/filter
-common_pid == 0
-
-Attempt to set a filter using a non-common field for all events in the
-sched subsystem (all events but those that have a prev_pid field retain
-their old filters):
-
-# cd /sys/kernel/debug/tracing/events/sched
-# echo prev_pid == 0 > filter
-# cat sched_switch/filter
-prev_pid == 0
-# cat sched_wakeup/filter
-common_pid == 0
-
-5.4 PID filtering
------------------
-
-The set_event_pid file in the same directory as the top events directory
-exists, will filter all events from tracing any task that does not have the
-PID listed in the set_event_pid file.
-
-# cd /sys/kernel/debug/tracing
-# echo $$ > set_event_pid
-# echo 1 > events/enabled
-
-Will only trace events for the current task.
-
-To add more PIDs without losing the PIDs already included, use '>>'.
-
-# echo 123 244 1 >> set_event_pid
-
-
-6. Event triggers
-=================
-
-Trace events can be made to conditionally invoke trigger 'commands'
-which can take various forms and are described in detail below;
-examples would be enabling or disabling other trace events or invoking
-a stack trace whenever the trace event is hit. Whenever a trace event
-with attached triggers is invoked, the set of trigger commands
-associated with that event is invoked. Any given trigger can
-additionally have an event filter of the same form as described in
-section 5 (Event filtering) associated with it - the command will only
-be invoked if the event being invoked passes the associated filter.
-If no filter is associated with the trigger, it always passes.
-
-Triggers are added to and removed from a particular event by writing
-trigger expressions to the 'trigger' file for the given event.
-
-A given event can have any number of triggers associated with it,
-subject to any restrictions that individual commands may have in that
-regard.
-
-Event triggers are implemented on top of "soft" mode, which means that
-whenever a trace event has one or more triggers associated with it,
-the event is activated even if it isn't actually enabled, but is
-disabled in a "soft" mode. That is, the tracepoint will be called,
-but just will not be traced, unless of course it's actually enabled.
-This scheme allows triggers to be invoked even for events that aren't
-enabled, and also allows the current event filter implementation to be
-used for conditionally invoking triggers.
-
-The syntax for event triggers is roughly based on the syntax for
-set_ftrace_filter 'ftrace filter commands' (see the 'Filter commands'
-section of Documentation/trace/ftrace.txt), but there are major
-differences and the implementation isn't currently tied to it in any
-way, so beware about making generalizations between the two.
-
-6.1 Expression syntax
----------------------
-
-Triggers are added by echoing the command to the 'trigger' file:
-
- # echo 'command[:count] [if filter]' > trigger
-
-Triggers are removed by echoing the same command but starting with '!'
-to the 'trigger' file:
-
- # echo '!command[:count] [if filter]' > trigger
-
-The [if filter] part isn't used in matching commands when removing, so
-leaving that off in a '!' command will accomplish the same thing as
-having it in.
-
-The filter syntax is the same as that described in the 'Event
-filtering' section above.
-
-For ease of use, writing to the trigger file using '>' currently just
-adds or removes a single trigger and there's no explicit '>>' support
-('>' actually behaves like '>>') or truncation support to remove all
-triggers (you have to use '!' for each one added.)
-
-6.2 Supported trigger commands
-------------------------------
-
-The following commands are supported:
-
-- enable_event/disable_event
-
- These commands can enable or disable another trace event whenever
- the triggering event is hit. When these commands are registered,
- the other trace event is activated, but disabled in a "soft" mode.
- That is, the tracepoint will be called, but just will not be traced.
- The event tracepoint stays in this mode as long as there's a trigger
- in effect that can trigger it.
-
- For example, the following trigger causes kmalloc events to be
- traced when a read system call is entered, and the :1 at the end
- specifies that this enablement happens only once:
-
- # echo 'enable_event:kmem:kmalloc:1' > \
- /sys/kernel/debug/tracing/events/syscalls/sys_enter_read/trigger
-
- The following trigger causes kmalloc events to stop being traced
- when a read system call exits. This disablement happens on every
- read system call exit:
-
- # echo 'disable_event:kmem:kmalloc' > \
- /sys/kernel/debug/tracing/events/syscalls/sys_exit_read/trigger
-
- The format is:
-
- enable_event:<system>:<event>[:count]
- disable_event:<system>:<event>[:count]
-
- To remove the above commands:
-
- # echo '!enable_event:kmem:kmalloc:1' > \
- /sys/kernel/debug/tracing/events/syscalls/sys_enter_read/trigger
-
- # echo '!disable_event:kmem:kmalloc' > \
- /sys/kernel/debug/tracing/events/syscalls/sys_exit_read/trigger
-
- Note that there can be any number of enable/disable_event triggers
- per triggering event, but there can only be one trigger per
- triggered event. e.g. sys_enter_read can have triggers enabling both
- kmem:kmalloc and sched:sched_switch, but can't have two kmem:kmalloc
- versions such as kmem:kmalloc and kmem:kmalloc:1 or 'kmem:kmalloc if
- bytes_req == 256' and 'kmem:kmalloc if bytes_alloc == 256' (they
- could be combined into a single filter on kmem:kmalloc though).
-
-- stacktrace
-
- This command dumps a stacktrace in the trace buffer whenever the
- triggering event occurs.
-
- For example, the following trigger dumps a stacktrace every time the
- kmalloc tracepoint is hit:
-
- # echo 'stacktrace' > \
- /sys/kernel/debug/tracing/events/kmem/kmalloc/trigger
-
- The following trigger dumps a stacktrace the first 5 times a kmalloc
- request happens with a size >= 64K
-
- # echo 'stacktrace:5 if bytes_req >= 65536' > \
- /sys/kernel/debug/tracing/events/kmem/kmalloc/trigger
-
- The format is:
-
- stacktrace[:count]
-
- To remove the above commands:
-
- # echo '!stacktrace' > \
- /sys/kernel/debug/tracing/events/kmem/kmalloc/trigger
-
- # echo '!stacktrace:5 if bytes_req >= 65536' > \
- /sys/kernel/debug/tracing/events/kmem/kmalloc/trigger
-
- The latter can also be removed more simply by the following (without
- the filter):
-
- # echo '!stacktrace:5' > \
- /sys/kernel/debug/tracing/events/kmem/kmalloc/trigger
-
- Note that there can be only one stacktrace trigger per triggering
- event.
-
-- snapshot
-
- This command causes a snapshot to be triggered whenever the
- triggering event occurs.
-
- The following command creates a snapshot every time a block request
- queue is unplugged with a depth > 1. If you were tracing a set of
- events or functions at the time, the snapshot trace buffer would
- capture those events when the trigger event occurred:
-
- # echo 'snapshot if nr_rq > 1' > \
- /sys/kernel/debug/tracing/events/block/block_unplug/trigger
-
- To only snapshot once:
-
- # echo 'snapshot:1 if nr_rq > 1' > \
- /sys/kernel/debug/tracing/events/block/block_unplug/trigger
-
- To remove the above commands:
-
- # echo '!snapshot if nr_rq > 1' > \
- /sys/kernel/debug/tracing/events/block/block_unplug/trigger
-
- # echo '!snapshot:1 if nr_rq > 1' > \
- /sys/kernel/debug/tracing/events/block/block_unplug/trigger
-
- Note that there can be only one snapshot trigger per triggering
- event.
-
-- traceon/traceoff
-
- These commands turn tracing on and off when the specified events are
- hit. The parameter determines how many times the tracing system is
- turned on and off. If unspecified, there is no limit.
-
- The following command turns tracing off the first time a block
- request queue is unplugged with a depth > 1. If you were tracing a
- set of events or functions at the time, you could then examine the
- trace buffer to see the sequence of events that led up to the
- trigger event:
-
- # echo 'traceoff:1 if nr_rq > 1' > \
- /sys/kernel/debug/tracing/events/block/block_unplug/trigger
-
- To always disable tracing when nr_rq > 1 :
-
- # echo 'traceoff if nr_rq > 1' > \
- /sys/kernel/debug/tracing/events/block/block_unplug/trigger
-
- To remove the above commands:
-
- # echo '!traceoff:1 if nr_rq > 1' > \
- /sys/kernel/debug/tracing/events/block/block_unplug/trigger
-
- # echo '!traceoff if nr_rq > 1' > \
- /sys/kernel/debug/tracing/events/block/block_unplug/trigger
-
- Note that there can be only one traceon or traceoff trigger per
- triggering event.
-
-- hist
-
- This command aggregates event hits into a hash table keyed on one or
- more trace event format fields (or stacktrace) and a set of running
- totals derived from one or more trace event format fields and/or
- event counts (hitcount).
-
- The format of a hist trigger is as follows:
-
- hist:keys=<field1[,field2,...]>[:values=<field1[,field2,...]>]
- [:sort=<field1[,field2,...]>][:size=#entries][:pause][:continue]
- [:clear][:name=histname1] [if <filter>]
-
- When a matching event is hit, an entry is added to a hash table
- using the key(s) and value(s) named. Keys and values correspond to
- fields in the event's format description. Values must correspond to
- numeric fields - on an event hit, the value(s) will be added to a
- sum kept for that field. The special string 'hitcount' can be used
- in place of an explicit value field - this is simply a count of
- event hits. If 'values' isn't specified, an implicit 'hitcount'
- value will be automatically created and used as the only value.
- Keys can be any field, or the special string 'stacktrace', which
- will use the event's kernel stacktrace as the key. The keywords
- 'keys' or 'key' can be used to specify keys, and the keywords
- 'values', 'vals', or 'val' can be used to specify values. Compound
- keys consisting of up to two fields can be specified by the 'keys'
- keyword. Hashing a compound key produces a unique entry in the
- table for each unique combination of component keys, and can be
- useful for providing more fine-grained summaries of event data.
- Additionally, sort keys consisting of up to two fields can be
- specified by the 'sort' keyword. If more than one field is
- specified, the result will be a 'sort within a sort': the first key
- is taken to be the primary sort key and the second the secondary
- key. If a hist trigger is given a name using the 'name' parameter,
- its histogram data will be shared with other triggers of the same
- name, and trigger hits will update this common data. Only triggers
- with 'compatible' fields can be combined in this way; triggers are
- 'compatible' if the fields named in the trigger share the same
- number and type of fields and those fields also have the same names.
- Note that any two events always share the compatible 'hitcount' and
- 'stacktrace' fields and can therefore be combined using those
- fields, however pointless that may be.
-
- 'hist' triggers add a 'hist' file to each event's subdirectory.
- Reading the 'hist' file for the event will dump the hash table in
- its entirety to stdout. If there are multiple hist triggers
- attached to an event, there will be a table for each trigger in the
- output. The table displayed for a named trigger will be the same as
- any other instance having the same name. Each printed hash table
- entry is a simple list of the keys and values comprising the entry;
- keys are printed first and are delineated by curly braces, and are
- followed by the set of value fields for the entry. By default,
- numeric fields are displayed as base-10 integers. This can be
- modified by appending any of the following modifiers to the field
- name:
-
- .hex display a number as a hex value
- .sym display an address as a symbol
- .sym-offset display an address as a symbol and offset
- .syscall display a syscall id as a system call name
- .execname display a common_pid as a program name
-
- Note that in general the semantics of a given field aren't
- interpreted when applying a modifier to it, but there are some
- restrictions to be aware of in this regard:
-
- - only the 'hex' modifier can be used for values (because values
- are essentially sums, and the other modifiers don't make sense
- in that context).
- - the 'execname' modifier can only be used on a 'common_pid'. The
- reason for this is that the execname is simply the 'comm' value
- saved for the 'current' process when an event was triggered,
- which is the same as the common_pid value saved by the event
- tracing code. Trying to apply that comm value to other pid
- values wouldn't be correct, and typically events that care save
- pid-specific comm fields in the event itself.
-
- A typical usage scenario would be the following to enable a hist
- trigger, read its current contents, and then turn it off:
-
- # echo 'hist:keys=skbaddr.hex:vals=len' > \
- /sys/kernel/debug/tracing/events/net/netif_rx/trigger
-
- # cat /sys/kernel/debug/tracing/events/net/netif_rx/hist
-
- # echo '!hist:keys=skbaddr.hex:vals=len' > \
- /sys/kernel/debug/tracing/events/net/netif_rx/trigger
-
- The trigger file itself can be read to show the details of the
- currently attached hist trigger. This information is also displayed
- at the top of the 'hist' file when read.
-
- By default, the size of the hash table is 2048 entries. The 'size'
- parameter can be used to specify more or fewer than that. The units
- are in terms of hashtable entries - if a run uses more entries than
- specified, the results will show the number of 'drops', the number
- of hits that were ignored. The size should be a power of 2 between
- 128 and 131072 (any non- power-of-2 number specified will be rounded
- up).
-
- The 'sort' parameter can be used to specify a value field to sort
- on. The default if unspecified is 'hitcount' and the default sort
- order is 'ascending'. To sort in the opposite direction, append
- .descending' to the sort key.
-
- The 'pause' parameter can be used to pause an existing hist trigger
- or to start a hist trigger but not log any events until told to do
- so. 'continue' or 'cont' can be used to start or restart a paused
- hist trigger.
-
- The 'clear' parameter will clear the contents of a running hist
- trigger and leave its current paused/active state.
-
- Note that the 'pause', 'cont', and 'clear' parameters should be
- applied using 'append' shell operator ('>>') if applied to an
- existing trigger, rather than via the '>' operator, which will cause
- the trigger to be removed through truncation.
-
-- enable_hist/disable_hist
-
- The enable_hist and disable_hist triggers can be used to have one
- event conditionally start and stop another event's already-attached
- hist trigger. Any number of enable_hist and disable_hist triggers
- can be attached to a given event, allowing that event to kick off
- and stop aggregations on a host of other events.
-
- The format is very similar to the enable/disable_event triggers:
-
- enable_hist:<system>:<event>[:count]
- disable_hist:<system>:<event>[:count]
-
- Instead of enabling or disabling the tracing of the target event
- into the trace buffer as the enable/disable_event triggers do, the
- enable/disable_hist triggers enable or disable the aggregation of
- the target event into a hash table.
-
- A typical usage scenario for the enable_hist/disable_hist triggers
- would be to first set up a paused hist trigger on some event,
- followed by an enable_hist/disable_hist pair that turns the hist
- aggregation on and off when conditions of interest are hit:
-
- # echo 'hist:keys=skbaddr.hex:vals=len:pause' > \
- /sys/kernel/debug/tracing/events/net/netif_receive_skb/trigger
-
- # echo 'enable_hist:net:netif_receive_skb if filename==/usr/bin/wget' > \
- /sys/kernel/debug/tracing/events/sched/sched_process_exec/trigger
-
- # echo 'disable_hist:net:netif_receive_skb if comm==wget' > \
- /sys/kernel/debug/tracing/events/sched/sched_process_exit/trigger
-
- The above sets up an initially paused hist trigger which is unpaused
- and starts aggregating events when a given program is executed, and
- which stops aggregating when the process exits and the hist trigger
- is paused again.
-
- The examples below provide a more concrete illustration of the
- concepts and typical usage patterns discussed above.
-
-
-6.2 'hist' trigger examples
----------------------------
-
- The first set of examples creates aggregations using the kmalloc
- event. The fields that can be used for the hist trigger are listed
- in the kmalloc event's format file:
-
- # cat /sys/kernel/debug/tracing/events/kmem/kmalloc/format
- name: kmalloc
- ID: 374
- format:
- field:unsigned short common_type; offset:0; size:2; signed:0;
- field:unsigned char common_flags; offset:2; size:1; signed:0;
- field:unsigned char common_preempt_count; offset:3; size:1; signed:0;
- field:int common_pid; offset:4; size:4; signed:1;
-
- field:unsigned long call_site; offset:8; size:8; signed:0;
- field:const void * ptr; offset:16; size:8; signed:0;
- field:size_t bytes_req; offset:24; size:8; signed:0;
- field:size_t bytes_alloc; offset:32; size:8; signed:0;
- field:gfp_t gfp_flags; offset:40; size:4; signed:0;
-
- We'll start by creating a hist trigger that generates a simple table
- that lists the total number of bytes requested for each function in
- the kernel that made one or mor
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