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Hagen Paul Pfeifer 26567ed79d perf script: Introduce --deltatime option 
For some kind of analysis a deltatime output is more human friendly and
reduce the cognitive load for further analysis.

The following output demonstrate the new option "deltatime": calculate
the time difference in relation to the previous event.

  $ perf script --deltatime
  test  2525 [001]     0.000000:            sdt_libev:ev_add: (5635e72a5ebd)
  test  2525 [001]     0.000091:  sdt_libev:epoll_wait_enter: (5635e72a76a9)
  test  2525 [001]     1.000051: sdt_libev:epoll_wait_return: (5635e72a772e) arg1=1
  test  2525 [001]     0.000685:            sdt_libev:ev_add: (5635e72a5ebd)
  test  2525 [001]     0.000048:  sdt_libev:epoll_wait_enter: (5635e72a76a9)
  test  2525 [001]     1.000104: sdt_libev:epoll_wait_return: (5635e72a772e) arg1=1
  test  2525 [001]     0.003895:  sdt_libev:epoll_wait_enter: (5635e72a76a9)
  test  2525 [001]     0.996034: sdt_libev:epoll_wait_return: (5635e72a772e) arg1=1
  test  2525 [001]     0.000058:  sdt_libev:epoll_wait_enter: (5635e72a76a9)
  test  2525 [001]     1.000004: sdt_libev:epoll_wait_return: (5635e72a772e) arg1=1
  test  2525 [001]     0.000064:  sdt_libev:epoll_wait_enter: (5635e72a76a9)
  test  2525 [001]     0.999934: sdt_libev:epoll_wait_return: (5635e72a772e) arg1=1
  test  2525 [001]     0.000056:  sdt_libev:epoll_wait_enter: (5635e72a76a9)
  test  2525 [001]     0.999930: sdt_libev:epoll_wait_return: (5635e72a772e) arg1=1

Committer testing:

So go from default output to --reltime and then this new --deltatime, to
contrast the various timestamp presentation modes for a random perf.data file I
had laying around:

  [root@five ~]# perf script --reltime | head
     perf 442394 [000]     0.000000:   16 cycles: ffffffff9706e544 native_write_msr+0x4 (/usr/lib/debug/lib/modules/5.5.10-200.fc31.x86_64/vmlinux)
     perf 442394 [000]     0.000002:   16 cycles: ffffffff9706e544 native_write_msr+0x4 (/usr/lib/debug/lib/modules/5.5.10-200.fc31.x86_64/vmlinux)
     perf 442394 [000]     0.000004:   16 cycles: ffffffff9706e544 native_write_msr+0x4 (/usr/lib/debug/lib/modules/5.5.10-200.fc31.x86_64/vmlinux)
     perf 442394 [000]     0.000006:  128 cycles: ffffffff972415a1 perf_event_update_userpage+0x1 (/usr/lib/debug/lib/modules/5.5.10-200.fc31.x86_64/vmlinux)
     perf 442394 [000]     0.000009: 2597 cycles: ffffffff97463785 cap_task_setscheduler+0x5 (/usr/lib/debug/lib/modules/5.5.10-200.fc31.x86_64/vmlinux)
     perf 442394 [001]     0.000036:   16 cycles: ffffffff9706e544 native_write_msr+0x4 (/usr/lib/debug/lib/modules/5.5.10-200.fc31.x86_64/vmlinux)
     perf 442394 [001]     0.000038:   16 cycles: ffffffff9706e544 native_write_msr+0x4 (/usr/lib/debug/lib/modules/5.5.10-200.fc31.x86_64/vmlinux)
     perf 442394 [001]     0.000040:   16 cycles: ffffffff9706e544 native_write_msr+0x4 (/usr/lib/debug/lib/modules/5.5.10-200.fc31.x86_64/vmlinux)
     perf 442394 [001]     0.000041:  224 cycles: ffffffff9700a53a perf_ibs_handle_irq+0x1da (/usr/lib/debug/lib/modules/5.5.10-200.fc31.x86_64/vmlinux)
     perf 442394 [001]     0.000044: 4439 cycles: ffffffff97120d85 put_prev_entity+0x45 (/usr/lib/debug/lib/modules/5.5.10-200.fc31.x86_64/vmlinux)
  [root@five ~]# perf script --deltatime | head
     perf 442394 [000]     0.000000:   16 cycles: ffffffff9706e544 native_write_msr+0x4 (/usr/lib/debug/lib/modules/5.5.10-200.fc31.x86_64/vmlinux)
     perf 442394 [000]     0.000002:   16 cycles: ffffffff9706e544 native_write_msr+0x4 (/usr/lib/debug/lib/modules/5.5.10-200.fc31.x86_64/vmlinux)
     perf 442394 [000]     0.000001:   16 cycles: ffffffff9706e544 native_write_msr+0x4 (/usr/lib/debug/lib/modules/5.5.10-200.fc31.x86_64/vmlinux)
     perf 442394 [000]     0.000001:  128 cycles: ffffffff972415a1 perf_event_update_userpage+0x1 (/usr/lib/debug/lib/modules/5.5.10-200.fc31.x86_64/vmlinux)
     perf 442394 [000]     0.000002: 2597 cycles: ffffffff97463785 cap_task_setscheduler+0x5 (/usr/lib/debug/lib/modules/5.5.10-200.fc31.x86_64/vmlinux)
     perf 442394 [001]     0.000027:   16 cycles: ffffffff9706e544 native_write_msr+0x4 (/usr/lib/debug/lib/modules/5.5.10-200.fc31.x86_64/vmlinux)
     perf 442394 [001]     0.000002:   16 cycles: ffffffff9706e544 native_write_msr+0x4 (/usr/lib/debug/lib/modules/5.5.10-200.fc31.x86_64/vmlinux)
     perf 442394 [001]     0.000001:   16 cycles: ffffffff9706e544 native_write_msr+0x4 (/usr/lib/debug/lib/modules/5.5.10-200.fc31.x86_64/vmlinux)
     perf 442394 [001]     0.000001:  224 cycles: ffffffff9700a53a perf_ibs_handle_irq+0x1da (/usr/lib/debug/lib/modules/5.5.10-200.fc31.x86_64/vmlinux)
     perf 442394 [001]     0.000002: 4439 cycles: ffffffff97120d85 put_prev_entity+0x45 (/usr/lib/debug/lib/modules/5.5.10-200.fc31.x86_64/vmlinux)
  [root@five ~]# perf script | head
     perf 442394 [000]  7600.157861:   16 cycles: ffffffff9706e544 native_write_msr+0x4 (/usr/lib/debug/lib/modules/5.5.10-200.fc31.x86_64/vmlinux)
     perf 442394 [000]  7600.157864:   16 cycles: ffffffff9706e544 native_write_msr+0x4 (/usr/lib/debug/lib/modules/5.5.10-200.fc31.x86_64/vmlinux)
     perf 442394 [000]  7600.157866:   16 cycles: ffffffff9706e544 native_write_msr+0x4 (/usr/lib/debug/lib/modules/5.5.10-200.fc31.x86_64/vmlinux)
     perf 442394 [000]  7600.157867:  128 cycles: ffffffff972415a1 perf_event_update_userpage+0x1 (/usr/lib/debug/lib/modules/5.5.10-200.fc31.x86_64/vmlinux)
     perf 442394 [000]  7600.157870: 2597 cycles: ffffffff97463785 cap_task_setscheduler+0x5 (/usr/lib/debug/lib/modules/5.5.10-200.fc31.x86_64/vmlinux)
     perf 442394 [001]  7600.157897:   16 cycles: ffffffff9706e544 native_write_msr+0x4 (/usr/lib/debug/lib/modules/5.5.10-200.fc31.x86_64/vmlinux)
     perf 442394 [001]  7600.157900:   16 cycles: ffffffff9706e544 native_write_msr+0x4 (/usr/lib/debug/lib/modules/5.5.10-200.fc31.x86_64/vmlinux)
     perf 442394 [001]  7600.157901:   16 cycles: ffffffff9706e544 native_write_msr+0x4 (/usr/lib/debug/lib/modules/5.5.10-200.fc31.x86_64/vmlinux)
     perf 442394 [001]  7600.157903:  224 cycles: ffffffff9700a53a perf_ibs_handle_irq+0x1da (/usr/lib/debug/lib/modules/5.5.10-200.fc31.x86_64/vmlinux)
     perf 442394 [001]  7600.157906: 4439 cycles: ffffffff97120d85 put_prev_entity+0x45 (/usr/lib/debug/lib/modules/5.5.10-200.fc31.x86_64/vmlinux)
  [root@five ~]#

Andi suggested we better implement it as a new field, i.e. -F deltatime, like:

  [root@five ~]# perf script -F deltatime
  Invalid field requested.

   Usage: perf script [<options>]
      or: perf script [<options>] record <script> [<record-options>] <command>
      or: perf script [<options>] report <script> [script-args]
      or: perf script [<options>] <script> [<record-options>] <command>
      or: perf script [<options>] <top-script> [script-args]

      -F, --fields <str>    comma separated output fields prepend with 'type:'. +field to add and -field to remove.Valid types: hw,sw,trace,raw,synth. Fields: comm,tid,pid,time,cpu,event,trace,ip,sym,dso,addr,symoff,srcline,period,iregs,uregs,brstack,brstacksym,flags,bpf-output,brstackinsn,brstackoff,callindent,insn,insnlen,synth,phys_addr,metric,misc,ipc
  [root@five ~]#

I.e. we have -F for maximum flexibility:

  [root@five ~]# perf script -F comm,pid,cpu,time | head
            perf 442394 [000]  7600.157861:
            perf 442394 [000]  7600.157864:
            perf 442394 [000]  7600.157866:
            perf 442394 [000]  7600.157867:
            perf 442394 [000]  7600.157870:
            perf 442394 [001]  7600.157897:
            perf 442394 [001]  7600.157900:
            perf 442394 [001]  7600.157901:
            perf 442394 [001]  7600.157903:
            perf 442394 [001]  7600.157906:
  [root@five ~]#

But since we already have --reltime, having --deltatime, documented one after
the other is sensible.

Signed-off-by: Hagen Paul Pfeifer <hagen@jauu.net>
Tested-by: Arnaldo Carvalho de Melo <acme@redhat.com>
Cc: Adrian Hunter <adrian.hunter@intel.com>
Cc: Andi Kleen <ak@linux.intel.com>
Cc: Jiri Olsa <jolsa@kernel.org>
Link: http://lore.kernel.org/lkml/20200204173709.489161-1-hagen@jauu.net
[ Added 'perf script' man page entry for --deltatime ]
Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>
2020-03-27 10:38:47 -03:00
arch x86/insn: Add Control-flow Enforcement (CET) instructions to the opcode map 2020-03-27 10:38:46 -03:00
block block: Fix partition support for host aware zoned block devices 2020-03-12 07:54:39 -06:00
certs certs: Add wrapper function to check blacklisted binary hash 2019-11-12 12:25:50 +11:00
crypto Merge branch 'next-integrity' of git://git.kernel.org/pub/scm/linux/kernel/git/zohar/linux-integrity 2020-02-20 15:15:16 -08:00
Documentation A single commit to handle an erratum in Cavium ThunderX to prevent access 2020-03-15 13:15:16 -07:00
drivers Merge branch 'for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/hid/hid 2020-03-17 09:38:03 -07:00
fs Fix for yet another subtle futex issue. The futex code used ihold() to 2020-03-15 12:55:52 -07:00
include Merge branch 'perf/urgent' into perf/core, to pick up fixes 2020-03-19 15:01:45 +01:00
init Tracing updates: 2020-02-26 10:34:42 -08:00
ipc Revert "ipc,sem: remove uneeded sem_undo_list lock usage in exit_sem()" 2020-02-21 11:22:15 -08:00
kernel perf/core: Fix reversed NULL check in perf_event_groups_less() 2020-03-20 13:06:22 +01:00
lib lib: Introduce generic min-heap 2020-03-06 11:56:59 +01:00
LICENSES LICENSES: Rename other to deprecated 2019-05-03 06:34:32 -06:00
mm Merge git://git.kernel.org/pub/scm/linux/kernel/git/netdev/net 2020-03-12 16:19:19 -07:00
net taprio: Fix sending packets without dequeueing them 2020-03-12 11:25:08 -07:00
samples Kbuild updates for v5.6 (2nd) 2020-02-09 16:05:50 -08:00
scripts parse-maintainers: Mark as executable 2020-03-06 16:29:21 -06:00
security Merge branch 'next-integrity' of git://git.kernel.org/pub/scm/linux/kernel/git/zohar/linux-integrity 2020-02-20 15:15:16 -08:00
sound ASoC: Fixes for v5.6 2020-03-07 07:24:36 +01:00
tools perf script: Introduce --deltatime option 2020-03-27 10:38:47 -03:00
usr Kbuild updates for v5.6 (2nd) 2020-02-09 16:05:50 -08:00
virt KVM/arm fixes for 5.6, take #1 2020-02-28 11:50:06 +01:00
.clang-format clang-format: Update with the latest for_each macro list 2020-03-06 21:50:05 +01:00
.cocciconfig
.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 selftest/lkdtm: Use local .gitignore 2020-03-02 08:39:39 -07:00
.mailmap A handful of small documentation fixes that wandered in. 2020-02-07 13:03:10 -08:00
COPYING COPYING: state that all contributions really are covered by this file 2020-02-10 13:32:20 -08:00
CREDITS MAINTAINERS: Hand MIPS over to Thomas 2020-02-24 22:43:18 -08:00
Kbuild kbuild: rename hostprogs-y/always to hostprogs/always-y 2020-02-04 01:53:07 +09:00
Kconfig docs: kbuild: convert docs to ReST and rename to *.rst 2019-06-14 14:21:21 -06:00
MAINTAINERS Merge git://git.kernel.org/pub/scm/linux/kernel/git/netdev/net 2020-03-12 16:19:19 -07:00
Makefile Linux 5.6-rc6 2020-03-15 15:01:23 -07:00
README Drop all 00-INDEX files from Documentation/ 2018-09-09 15:08:58 -06:00

README 

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.