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* [PATCH RFC 0/6] perf/x86: Add perf text poke event
@ 2019-10-25 12:59 Adrian Hunter
  2019-10-25 12:59 ` [PATCH RFC 1/6] " Adrian Hunter
                   ` (5 more replies)
  0 siblings, 6 replies; 34+ messages in thread
From: Adrian Hunter @ 2019-10-25 12:59 UTC (permalink / raw)
  To: Peter Zijlstra
  Cc: Ingo Molnar, Borislav Petkov, H . Peter Anvin, x86, Mark Rutland,
	Alexander Shishkin, Mathieu Poirier, Leo Yan,
	Arnaldo Carvalho de Melo, Jiri Olsa, linux-kernel

Hi

Here are patches to add a text poke event to record changes to kernel text
(i.e. self-modifying code) in order to support tracers like Intel PT
decoding through jump labels.

One question is whether this approach can be of use to other architectures,
particularly ARM-CS.

The first patch makes the kernel change and the subsequent patches are
tools changes.

The first 3 tools patches add support for updating perf tools' data cache
with the changed bytes.

The last 2 patches are Intel PT specific tools changes.

The patches are based on Arnaldo's tree perf/core branch.

Example:

  For jump labels, the kernel needs
	CONFIG_JUMP_LABEL=y
  and also an easy to flip jump label is in sysctl_schedstats() which needs
	CONFIG_SCHEDSTATS=y
	CONFIG_PROC_SYSCTL=y

  Also note the 'sudo perf record' is put into the background which, as
  written, needs sudo credential caching (otherwise the background task
  will stop awaiting the sudo password), hence the 'sudo echo' to start.

Before:

  $ sudo echo
  $ sudo perf record -o perf.data.before --kcore -a -e intel_pt//k -m,64M &
  [1] 1640
  $ cat /proc/sys/kernel/sched_schedstats
  0
  $ sudo bash -c 'echo 1 > /proc/sys/kernel/sched_schedstats'
  $ cat /proc/sys/kernel/sched_schedstats
  1
  $ sudo bash -c 'echo 0 > /proc/sys/kernel/sched_schedstats'
  $ cat /proc/sys/kernel/sched_schedstats
  0
  $ sudo kill 1640
  [ perf record: Woken up 1 times to write data ]
  [ perf record: Captured and wrote 16.635 MB perf.data.before ]
  $ perf script -i perf.data.before --itrace=e >/dev/null
  Warning:
  1946 instruction trace errors

After:

  $ sudo echo
  $ sudo perf record -o perf.data.after --kcore -a -e intel_pt//k -m,64M &
  [1] 1882
  $ cat /proc/sys/kernel/sched_schedstats
  0
  $ sudo bash -c 'echo 1 > /proc/sys/kernel/sched_schedstats'
  $ cat /proc/sys/kernel/sched_schedstats
  1
  $ sudo bash -c 'echo 0 > /proc/sys/kernel/sched_schedstats'
  $ cat /proc/sys/kernel/sched_schedstats
  0
  $ sudo kill 1882
  [ perf record: Woken up 1 times to write data ]
  [ perf record: Captured and wrote 10.893 MB perf.data.after ]
  $ perf script -i perf.data.after --itrace=e
  $


Adrian Hunter (6):
      perf/x86: Add perf text poke event
      perf dso: Refactor dso_cache__read()
      perf dso: Add dso__data_write_cache_addr()
      perf tools: Add support for PERF_RECORD_TEXT_POKE
      perf auxtrace: Add auxtrace_cache__remove()
      perf intel-pt: Add support for text poke events

 arch/x86/include/asm/text-patching.h      |   1 +
 arch/x86/kernel/alternative.c             |  39 ++++++++-
 include/linux/perf_event.h                |   6 ++
 include/uapi/linux/perf_event.h           |  28 ++++++-
 kernel/events/core.c                      |  90 +++++++++++++++++++-
 tools/include/uapi/linux/perf_event.h     |  28 ++++++-
 tools/perf/arch/x86/util/intel-pt.c       |   5 ++
 tools/perf/builtin-record.c               |  45 ++++++++++
 tools/perf/lib/include/perf/event.h       |   9 ++
 tools/perf/util/auxtrace.c                |  28 +++++++
 tools/perf/util/auxtrace.h                |   1 +
 tools/perf/util/dso.c                     | 135 +++++++++++++++++++++---------
 tools/perf/util/dso.h                     |   7 ++
 tools/perf/util/event.c                   |  39 +++++++++
 tools/perf/util/event.h                   |   5 ++
 tools/perf/util/evlist.h                  |   1 +
 tools/perf/util/intel-pt.c                |  71 ++++++++++++++++
 tools/perf/util/machine.c                 |  38 +++++++++
 tools/perf/util/machine.h                 |   3 +
 tools/perf/util/perf_event_attr_fprintf.c |   1 +
 tools/perf/util/record.c                  |  10 +++
 tools/perf/util/record.h                  |   1 +
 tools/perf/util/session.c                 |  22 +++++
 tools/perf/util/tool.h                    |   3 +-
 24 files changed, 570 insertions(+), 46 deletions(-)


Regards
Adrian

^ permalink raw reply	[flat|nested] 34+ messages in thread

end of thread, other threads:[~2019-11-12 11:20 UTC | newest]

Thread overview: 34+ messages (download: mbox.gz / follow: Atom feed)
-- links below jump to the message on this page --
2019-10-25 12:59 [PATCH RFC 0/6] perf/x86: Add perf text poke event Adrian Hunter
2019-10-25 12:59 ` [PATCH RFC 1/6] " Adrian Hunter
2019-10-30 10:47   ` Leo Yan
2019-10-30 12:46     ` Peter Zijlstra
2019-10-30 14:19       ` Leo Yan
2019-10-30 15:00         ` Mike Leach
2019-10-30 16:23         ` Peter Zijlstra
2019-10-31  7:31           ` Leo Yan
2019-11-01 10:04             ` Peter Zijlstra
2019-11-01 10:09               ` Peter Zijlstra
2019-11-04  2:23               ` Leo Yan
2019-11-08 15:05                 ` Leo Yan
2019-11-11 14:46                   ` Peter Zijlstra
2019-11-11 15:39                     ` Will Deacon
2019-11-11 16:05                       ` Peter Zijlstra
2019-11-11 17:29                         ` Will Deacon
2019-11-11 20:32                           ` Peter Zijlstra
     [not found]             ` <CAJ9a7VgZH7g=rFDpKf=FzEcyBVLS_WjqbrqtRnjOi7WOY4st+w@mail.gmail.com>
2019-11-01 10:06               ` Peter Zijlstra
2019-11-04 10:40   ` Peter Zijlstra
2019-11-04 12:32     ` Adrian Hunter
2019-10-25 12:59 ` [PATCH RFC 2/6] perf dso: Refactor dso_cache__read() Adrian Hunter
2019-10-25 14:54   ` Arnaldo Carvalho de Melo
2019-10-28 15:39   ` Jiri Olsa
2019-10-29  9:19     ` Adrian Hunter
2019-11-12 11:18   ` [tip: perf/core] " tip-bot2 for Adrian Hunter
2019-10-25 12:59 ` [PATCH RFC 3/6] perf dso: Add dso__data_write_cache_addr() Adrian Hunter
2019-10-28 15:45   ` Jiri Olsa
2019-10-29  9:20     ` Adrian Hunter
2019-11-12 11:18   ` [tip: perf/core] " tip-bot2 for Adrian Hunter
2019-10-25 12:59 ` [PATCH RFC 4/6] perf tools: Add support for PERF_RECORD_TEXT_POKE Adrian Hunter
2019-10-25 12:59 ` [PATCH RFC 5/6] perf auxtrace: Add auxtrace_cache__remove() Adrian Hunter
2019-10-25 14:48   ` Arnaldo Carvalho de Melo
2019-11-12 11:18   ` [tip: perf/core] " tip-bot2 for Adrian Hunter
2019-10-25 13:00 ` [PATCH RFC 6/6] perf intel-pt: Add support for text poke events Adrian Hunter

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