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Hagen Paul Pfeifer 69f48c7040 perf script: Add min, max to futex-contention output, in addition to avg
Average is quite informative, but the outliners - especially max - are
also of interest.

Before:

  mutex-locker[793299] lock 5637ec61e080 contended 3400 times, 446 avg ns
  mutex-locker[793301] lock 5637ec61e080 contended 3563 times, 385 avg ns
  mutex-locker[793300] lock 5637ec61e080 contended 3110 times, 1855 avg ns

After:

  mutex-locker[795251] lock 55b14e6dd080 contended 3853 times, 1279 avg ns [max: 12270 ns, min 340 ns]
  mutex-locker[795253] lock 55b14e6dd080 contended 2911 times, 518 avg ns [max: 51660261 ns, min 347 ns]
  mutex-locker[795252] lock 55b14e6dd080 contended 3843 times, 385 avg ns [max: 24323998 ns, min 338 ns]

Committer testing:

  [root@five ~]# perf script record futex-contention -a
  ^C[ perf record: Woken up 1 times to write data ]
  [ perf record: Captured and wrote 1.877 MB perf.data (923 samples) ]

  [root@five ~]# perf evlist
  syscalls:sys_enter_futex
  syscalls:sys_exit_futex
  dummy:HG
  # Tip: use 'perf evlist --trace-fields' to show fields for tracepoint events
  #

Before:

  [root@five ~]# perf script report futex-contention
  JS Helper[2457] lock 55fe0cf82610 contended 4 times, 6657 avg ns
  ibus-daemon[2975] lock 56227f6d0210 contended 4 times, 1020 avg ns
  chromium-browse[1905801] lock 7ffe573f5088 contended 8 times, 108463 avg ns
  gnome-shell[2240] lock 55fe0cf82678 contended 1 times, 8616 avg ns
  gnome-shel:cs0[2292] lock 55fe0d0ab768 contended 3 times, 606016034 avg ns
  JS Helper[2458] lock 55fe0cf82690 contended 1 times, 1167840 avg ns
  chromium-browse[1905470] lock 7ffe573f5358 contended 1 times, 551504 avg ns
  chromium-browse[1905948] lock 7ffe573f5358 contended 1 times, 577422 avg ns
  gnome-shell[2240] lock 55fe0cf82660 contended 6 times, 202696 avg ns
  pool[2602] lock 7fd600008ef0 contended 1 times, 500046007 avg ns
  chromium-browse[1905801] lock 7ffe573f5128 contended 4 times, 285083 avg ns
  JS Helper[2460] lock 55fe0cf82690 contended 1 times, 680877 avg ns
  JS Helper[2459] lock 55fe0cf82610 contended 7 times, 4224 avg ns
  chromium-browse[1905434] lock 7ffe573f5358 contended 1 times, 697038 avg ns
  chromium-browse[212592] lock 7ffe573f53c8 contended 4 times, 460601 avg ns
  gnome-shel:cs0[2292] lock 55fe0d0ab76c contended 2 times, 601237648 avg ns
  JS Helper[2460] lock 55fe0cf82610 contended 4 times, 3340 avg ns
  JS Helper[2462] lock 55fe0cf82694 contended 1 times, 237275 avg ns
  chromium-browse[1905605] lock 7ffe573f5358 contended 2 times, 634555 avg ns
  chromium-browse[1905992] lock 7ffe573f5358 contended 1 times, 583965 avg ns
  chromium-browse[1905647] lock 7ffe573f5368 contended 8 times, 549800 avg ns
  JS Helper[2462] lock 55fe0cf82610 contended 2 times, 4694 avg ns
  JS Helper[2461] lock 55fe0cf82694 contended 1 times, 257793 avg ns
  JS Helper[2456] lock 55fe0cf82690 contended 1 times, 677771 avg ns
  JS Helper[2463] lock 55fe0cf82610 contended 3 times, 5139 avg ns
  gdbus[2980] lock 56227f6d0210 contended 2 times, 2465 avg ns
  gnome-shell[2240] lock 55fe0cf82664 contended 5 times, 8036 avg ns
  chromium-browse[1906308] lock 7ffe573f5358 contended 1 times, 210735 avg ns
  JS Helper[2463] lock 55fe0cf82694 contended 1 times, 251531 avg ns
  chromium-browse[1905801] lock 7ffe573f4f58 contended 4 times, 399927 avg ns
  [root@five ~]#

After:

  [root@five ~]# perf script report futex-contention
  JS Helper[2457] lock 55fe0cf82610 contended 4 times, 6657 avg ns [max: 11502 ns, min 792 ns]
  ibus-daemon[2975] lock 56227f6d0210 contended 4 times, 1020 avg ns [max: 1813 ns, min 581 ns]
  chromium-browse[1905801] lock 7ffe573f5088 contended 8 times, 108463 avg ns [max: 380103 ns, min 57989 ns]
  gnome-shell[2240] lock 55fe0cf82678 contended 1 times, 8616 avg ns [max: 8616 ns, min 8616 ns]
  gnome-shel:cs0[2292] lock 55fe0d0ab768 contended 3 times, 606016034 avg ns [max: 611295960 ns, min 600191357 ns]
  JS Helper[2458] lock 55fe0cf82690 contended 1 times, 1167840 avg ns [max: 1167840 ns, min 1167840 ns]
  chromium-browse[1905470] lock 7ffe573f5358 contended 1 times, 551504 avg ns [max: 551504 ns, min 551504 ns]
  chromium-browse[1905948] lock 7ffe573f5358 contended 1 times, 577422 avg ns [max: 577422 ns, min 577422 ns]
  gnome-shell[2240] lock 55fe0cf82660 contended 6 times, 202696 avg ns [max: 398998 ns, min 5050 ns]
  pool[2602] lock 7fd600008ef0 contended 1 times, 500046007 avg ns [max: 500046007 ns, min 500046007 ns]
  chromium-browse[1905801] lock 7ffe573f5128 contended 4 times, 285083 avg ns [max: 389531 ns, min 76183 ns]
  JS Helper[2460] lock 55fe0cf82690 contended 1 times, 680877 avg ns [max: 680877 ns, min 680877 ns]
  JS Helper[2459] lock 55fe0cf82610 contended 7 times, 4224 avg ns [max: 12724 ns, min 1012 ns]
  chromium-browse[1905434] lock 7ffe573f5358 contended 1 times, 697038 avg ns [max: 697038 ns, min 697038 ns]
  chromium-browse[212592] lock 7ffe573f53c8 contended 4 times, 460601 avg ns [max: 594956 ns, min 232996 ns]
  gnome-shel:cs0[2292] lock 55fe0d0ab76c contended 2 times, 601237648 avg ns [max: 601255863 ns, min 601219434 ns]
  JS Helper[2460] lock 55fe0cf82610 contended 4 times, 3340 avg ns [max: 9168 ns, min 962 ns]
  JS Helper[2462] lock 55fe0cf82694 contended 1 times, 237275 avg ns [max: 237275 ns, min 237275 ns]
  chromium-browse[1905605] lock 7ffe573f5358 contended 2 times, 634555 avg ns [max: 1024060 ns, min 245050 ns]
  chromium-browse[1905992] lock 7ffe573f5358 contended 1 times, 583965 avg ns [max: 583965 ns, min 583965 ns]
  chromium-browse[1905647] lock 7ffe573f5368 contended 8 times, 549800 avg ns [max: 775293 ns, min 258375 ns]
  JS Helper[2462] lock 55fe0cf82610 contended 2 times, 4694 avg ns [max: 8556 ns, min 832 ns]
  JS Helper[2461] lock 55fe0cf82694 contended 1 times, 257793 avg ns [max: 257793 ns, min 257793 ns]
  JS Helper[2456] lock 55fe0cf82690 contended 1 times, 677771 avg ns [max: 677771 ns, min 677771 ns]
  JS Helper[2463] lock 55fe0cf82610 contended 3 times, 5139 avg ns [max: 6873 ns, min 931 ns]
  gdbus[2980] lock 56227f6d0210 contended 2 times, 2465 avg ns [max: 4188 ns, min 742 ns]
  gnome-shell[2240] lock 55fe0cf82664 contended 5 times, 8036 avg ns [max: 13105 ns, min 401 ns]
  chromium-browse[1906308] lock 7ffe573f5358 contended 1 times, 210735 avg ns [max: 210735 ns, min 210735 ns]
  JS Helper[2463] lock 55fe0cf82694 contended 1 times, 251531 avg ns [max: 251531 ns, min 251531 ns]
  chromium-browse[1905801] lock 7ffe573f4f58 contended 4 times, 399927 avg ns [max: 476904 ns, min 178495 ns]
  [root@five ~]#

Signed-off-by: Hagen Paul Pfeifer <hagen@jauu.net>
Tested-by: Arnaldo Carvalho de Melo <acme@redhat.com>
Link: http://lore.kernel.org/lkml/20200922200922.1306034-1-hagen@jauu.net
Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>
2020-09-23 12:58:53 -03:00
arch vgacon: remove software scrollback support 2020-09-14 10:06:15 -07:00
block - Fix a regression in bdev partition locking (Christoph) 2020-09-11 11:55:28 -07:00
certs .gitignore: add SPDX License Identifier 2020-03-25 11:50:48 +01:00
crypto Merge branch 'linus' of git://git.kernel.org/pub/scm/linux/kernel/git/herbert/crypto-2.6 2020-08-30 15:53:44 -07:00
Documentation ARM: SoC fixes 2020-09-13 14:54:40 -07:00
drivers A handful of clk driver fixes. Mostly they're for error paths or 2020-09-16 11:52:56 -07:00
fs for-5.9-rc5-tag 2020-09-14 15:41:58 -07:00
include Driver core fixes for 5.9-rc5 2020-09-13 09:02:59 -07:00
init init: fix error check in clean_path() 2020-09-04 09:16:58 -07:00
ipc ipc: adjust proc_ipc_sem_dointvec definition to match prototype 2020-09-05 12:14:29 -07:00
kernel seccomp fixes for v5.9-rc5 2020-09-12 12:58:01 -07:00
lib Driver core fixes for 5.9-rc5 2020-09-13 09:02:59 -07:00
LICENSES LICENSES: Rename other to deprecated 2019-05-03 06:34:32 -06:00
mm xen: branch for v5.9-rc4 2020-09-06 09:59:27 -07:00
net NFS client bugfixes for Linux 5.9 2020-09-09 11:14:20 -07:00
samples treewide: Use fallthrough pseudo-keyword 2020-08-23 17:36:59 -05:00
scripts Char / Misc driver fixes for 5.9-rc5 2020-09-13 08:52:21 -07:00
security device_cgroup RCU warning fix from Amol Grover <frextrite@gmail.com> 2020-09-15 16:26:57 -07:00
sound sound fixes for 5.9-rc4 2020-09-04 12:05:25 -07:00
tools perf script: Add min, max to futex-contention output, in addition to avg 2020-09-23 12:58:53 -03:00
usr Merge branch 'work.fdpic' of git://git.kernel.org/pub/scm/linux/kernel/git/viro/vfs 2020-08-07 13:29:39 -07:00
virt KVM: fix memory leak in kvm_io_bus_unregister_dev() 2020-09-11 13:15:11 -04:00
.clang-format clang-format: Update with the latest for_each macro list 2020-09-01 12:53:42 +02:00
.cocciconfig scripts: add Linux .cocciconfig for coccinelle 2016-07-22 12:13:39 +02:00
.get_maintainer.ignore Opt out of scripts/get_maintainer.pl 2019-05-16 10:53:40 -07:00
.gitattributes .gitattributes: use 'dts' diff driver for dts files 2019-12-04 19:44:11 -08:00
.gitignore .gitignore: Add ZSTD-compressed files 2020-07-31 11:50:49 +02:00
.mailmap mailmap, MAINTAINERS: move to tycho.pizza 2020-09-08 11:29:57 -07:00
COPYING COPYING: state that all contributions really are covered by this file 2020-02-10 13:32:20 -08:00
CREDITS CREDITS: Replace HTTP links with HTTPS ones 2020-07-23 14:53:58 -06:00
Kbuild kbuild: rename hostprogs-y/always to hostprogs/always-y 2020-02-04 01:53:07 +09:00
Kconfig kbuild: ensure full rebuild when the compiler is updated 2020-05-12 13:28:33 +09:00
MAINTAINERS MAINTAINERS: Fix Max's and Shravan's emails 2020-09-16 11:51:02 -07:00
Makefile Linux 5.9-rc5 2020-09-13 16:06:00 -07:00
README Drop all 00-INDEX files from Documentation/ 2018-09-09 15:08:58 -06:00

Linux kernel
============

There are several guides for kernel developers and users. These guides can
be rendered in a number of formats, like HTML and PDF. Please read
Documentation/admin-guide/README.rst first.

In order to build the documentation, use ``make htmldocs`` or
``make pdfdocs``.  The formatted documentation can also be read online at:

    https://www.kernel.org/doc/html/latest/

There are various text files in the Documentation/ subdirectory,
several of them using the Restructured Text markup notation.

Please read the Documentation/process/changes.rst file, as it contains the
requirements for building and running the kernel, and information about
the problems which may result by upgrading your kernel.