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(-)
--
2.52.0.rc2.455.g230fcf2819-goog