[PATCHSET v6 0/6] perf tools: Add deferred callchain support

[Namhyung Kim <namhyung@kernel.org>]

Hello,

This is a new version of deferred callchain support as the kernel part
is merged to the tip tree.  Actually this is based on Steve's work (v16).

  https://lore.kernel.org/r/20250908175319.841517121@kernel.org

v6 changes)

* always copy the events  (Ian)
* add flush in the pipe mode

v5: https://lore.kernel.org/r/20251120021046.94490-1-namhyung@kernel.org/

* update delegate tools  (Ian)
* copy and flush remaining samples  (Ian)
* add Ian's Reviewed-by tags

v4: https://lore.kernel.org/r/20251115234106.348571-1-namhyung@kernel.org

* add --call-graph fp,defer option   (Ian, Steve)
* add more comment on the cookie  (Ian)
* display cookie part in the deferred callchain  (Ian)

v3: https://lore.kernel.org/r/20251114070018.160330-1-namhyung@kernel.org

* handle new attr.defer_output to generate deferred callchains
* fix crash when cookies don't match  (Steven)
* disable merging for perf inject
* fix missing feature detection bug
* symbolize merged callchains properly

Here's an example session.

  $ perf record --call-graph fp,defer  pwd
  /home/namhyung/project/linux
  [ perf record: Woken up 1 times to write data ]
  [ perf record: Captured and wrote 0.010 MB perf.data (29 samples) ]

  $ perf evlist -v
  cpu/cycles/P: type: 0 (PERF_TYPE_HARDWARE), size: 136, config: 0 (PERF_COUNT_HW_CPU_CYCLES),
  { sample_period, sample_freq }: 4000, sample_type: IP|TID|TIME|CALLCHAIN|PERIOD,
  read_format: ID|LOST, disabled: 1, inherit: 1, mmap: 1, comm: 1, freq: 1, enable_on_exec: 1,
  task: 1, sample_id_all: 1, mmap2: 1, comm_exec: 1, ksymbol: 1, bpf_event: 1, build_id: 1,
  defer_callchain: 1, defer_output: 1

  $ perf script
  ...
  pwd    2312   121.163435:     249113 cpu/cycles/P:
          ffffffff845b78d8 __build_id_parse.isra.0+0x218 ([kernel.kallsyms])
          ffffffff83bb5bf6 perf_event_mmap+0x2e6 ([kernel.kallsyms])
          ffffffff83c31959 mprotect_fixup+0x1e9 ([kernel.kallsyms])
          ffffffff83c31dc5 do_mprotect_pkey+0x2b5 ([kernel.kallsyms])
          ffffffff83c3206f __x64_sys_mprotect+0x1f ([kernel.kallsyms])
          ffffffff845e6692 do_syscall_64+0x62 ([kernel.kallsyms])
          ffffffff8360012f entry_SYSCALL_64_after_hwframe+0x76 ([kernel.kallsyms])
              7f18fe337fa7 mprotect+0x7 (/lib/x86_64-linux-gnu/ld-linux-x86-64.so.2)
              7f18fe330e0f _dl_sysdep_start+0x7f (/lib/x86_64-linux-gnu/ld-linux-x86-64.so.2)
              7f18fe331448 _dl_start_user+0x0 (/lib/x86_64-linux-gnu/ld-linux-x86-64.so.2)
  ...

  $ perf script --no-merge-callchains
  ...
  pwd    2312   121.163435:     249113 cpu/cycles/P:
          ffffffff845b78d8 __build_id_parse.isra.0+0x218 ([kernel.kallsyms])
          ffffffff83bb5bf6 perf_event_mmap+0x2e6 ([kernel.kallsyms])
          ffffffff83c31959 mprotect_fixup+0x1e9 ([kernel.kallsyms])
          ffffffff83c31dc5 do_mprotect_pkey+0x2b5 ([kernel.kallsyms])
          ffffffff83c3206f __x64_sys_mprotect+0x1f ([kernel.kallsyms])
          ffffffff845e6692 do_syscall_64+0x62 ([kernel.kallsyms])
          ffffffff8360012f entry_SYSCALL_64_after_hwframe+0x76 ([kernel.kallsyms])
                 b00000006 (cookie) ([unknown])

  pwd    2312   121.163447: DEFERRED CALLCHAIN [cookie: b00000006]
              7f18fe337fa7 mprotect+0x7 (/lib/x86_64-linux-gnu/ld-linux-x86-64.so.2)
              7f18fe330e0f _dl_sysdep_start+0x7f (/lib/x86_64-linux-gnu/ld-linux-x86-64.so.2)
              7f18fe331448 _dl_start_user+0x0 (/lib/x86_64-linux-gnu/ld-linux-x86-64.so.2)
  ...

The code is available at 'perf/defer-callchain-v6' branch in

  git.kernel.org/pub/scm/linux/kernel/git/namhyung/linux-perf.git

Thanks,
Namhyung


Namhyung Kim (6):
  tools headers UAPI: Sync linux/perf_event.h for deferred callchains
  perf tools: Minimal DEFERRED_CALLCHAIN support
  perf record: Add --call-graph fp,defer option for deferred callchains
  perf script: Display PERF_RECORD_CALLCHAIN_DEFERRED
  perf tools: Merge deferred user callchains
  perf tools: Flush remaining samples w/o deferred callchains

 tools/include/uapi/linux/perf_event.h     |  21 +++-
 tools/lib/perf/include/perf/event.h       |  13 ++
 tools/perf/Documentation/perf-config.txt  |   3 +
 tools/perf/Documentation/perf-record.txt  |   4 +
 tools/perf/Documentation/perf-script.txt  |   5 +
 tools/perf/builtin-inject.c               |   1 +
 tools/perf/builtin-report.c               |   1 +
 tools/perf/builtin-script.c               |  93 ++++++++++++++
 tools/perf/util/callchain.c               |  45 ++++++-
 tools/perf/util/callchain.h               |   4 +
 tools/perf/util/event.c                   |   1 +
 tools/perf/util/evlist.c                  |   1 +
 tools/perf/util/evlist.h                  |   2 +
 tools/perf/util/evsel.c                   |  50 +++++++-
 tools/perf/util/evsel.h                   |   1 +
 tools/perf/util/evsel_fprintf.c           |   5 +-
 tools/perf/util/machine.c                 |   1 +
 tools/perf/util/perf_event_attr_fprintf.c |   2 +
 tools/perf/util/sample.h                  |   2 +
 tools/perf/util/session.c                 | 147 ++++++++++++++++++++++
 tools/perf/util/tool.c                    |   5 +
 tools/perf/util/tool.h                    |   4 +-
 22 files changed, 403 insertions(+), 8 deletions(-)

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2.52.0.rc2.455.g230fcf2819-goog