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author | 2022-08-11 11:54:55 -0700 | |
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committer | 2022-08-11 17:57:34 -0300 | |
commit | d23477637ac6d29f946461a2fa5eb616cfa5d3f0 (patch) | |
tree | a59d3becba05f2582a67b935039dce47af19c04d /tools/perf/util/bpf_off_cpu.c | |
parent | perf offcpu: Parse process id separately (diff) | |
download | linux-d23477637ac6d29f946461a2fa5eb616cfa5d3f0.tar.gz linux-d23477637ac6d29f946461a2fa5eb616cfa5d3f0.tar.bz2 linux-d23477637ac6d29f946461a2fa5eb616cfa5d3f0.zip |
perf offcpu: Track child processes
When -p option used or a workload is given, it needs to handle child
processes. The perf_event can inherit those task events
automatically. We can add a new BPF program in task_newtask
tracepoint to track child processes.
Before:
$ sudo perf record --off-cpu -- perf bench sched messaging
$ sudo perf report --stat | grep -A1 offcpu
offcpu-time stats:
SAMPLE events: 1
After:
$ sudo perf record -a --off-cpu -- perf bench sched messaging
$ sudo perf report --stat | grep -A1 offcpu
offcpu-time stats:
SAMPLE events: 856
Signed-off-by: Namhyung Kim <namhyung@kernel.org>
Cc: Blake Jones <blakejones@google.com>
Cc: Hao Luo <haoluo@google.com>
Cc: Ian Rogers <irogers@google.com>
Cc: Ingo Molnar <mingo@kernel.org>
Cc: Jiri Olsa <jolsa@kernel.org>
Cc: Milian Wolff <milian.wolff@kdab.com>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Song Liu <songliubraving@fb.com>
Cc: bpf@vger.kernel.org
Link: https://lore.kernel.org/r/20220811185456.194721-4-namhyung@kernel.org
Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>
Diffstat (limited to 'tools/perf/util/bpf_off_cpu.c')
-rw-r--r-- | tools/perf/util/bpf_off_cpu.c | 7 |
1 files changed, 7 insertions, 0 deletions
diff --git a/tools/perf/util/bpf_off_cpu.c b/tools/perf/util/bpf_off_cpu.c index f7ee0c7a53f0..c257813e674e 100644 --- a/tools/perf/util/bpf_off_cpu.c +++ b/tools/perf/util/bpf_off_cpu.c @@ -17,6 +17,7 @@ #include "bpf_skel/off_cpu.skel.h" #define MAX_STACKS 32 +#define MAX_PROC 4096 /* we don't need actual timestamp, just want to put the samples at last */ #define OFF_CPU_TIMESTAMP (~0ull << 32) @@ -164,10 +165,16 @@ int off_cpu_prepare(struct evlist *evlist, struct target *target, ntasks++; } + + if (ntasks < MAX_PROC) + ntasks = MAX_PROC; + bpf_map__set_max_entries(skel->maps.task_filter, ntasks); } else if (target__has_task(target)) { ntasks = perf_thread_map__nr(evlist->core.threads); bpf_map__set_max_entries(skel->maps.task_filter, ntasks); + } else if (target__none(target)) { + bpf_map__set_max_entries(skel->maps.task_filter, MAX_PROC); } if (evlist__first(evlist)->cgrp) { |