diff options
| author | Namhyung Kim <namhyung@kernel.org> | 2022-08-11 21:54:53 +0300 |
|---|---|---|
| committer | Arnaldo Carvalho de Melo <acme@redhat.com> | 2022-08-11 23:56:47 +0300 |
| commit | 07fc958b0cfcd8e44f0de13625a551dd16b97eb4 (patch) | |
| tree | 901859b4c59030cefdb7ecf1cc33604676243aad | |
| parent | 806731a9465b42aaf887cbaf8bfee7eccc9417de (diff) | |
| download | linux-07fc958b0cfcd8e44f0de13625a551dd16b97eb4.tar.xz | |
perf offcpu: Check process id for the given workload
Current task filter checks task->pid which is different for each
thread. But we want to profile all the threads in the process. So
let's compare process id (or thread-group id: tgid) instead.
Before:
$ sudo perf record --off-cpu -- perf bench sched messaging -t
$ sudo perf report --stat | grep -A1 offcpu
offcpu-time stats:
SAMPLE events: 2
After:
$ sudo perf record --off-cpu -- perf bench sched messaging -t
$ sudo perf report --stat | grep -A1 offcpu
offcpu-time stats:
SAMPLE events: 850
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/20220811185456.194721-2-namhyung@kernel.org
Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>
| -rw-r--r-- | tools/perf/util/bpf_off_cpu.c | 1 | ||||
| -rw-r--r-- | tools/perf/util/bpf_skel/off_cpu.bpf.c | 8 |
2 files changed, 8 insertions, 1 deletions
diff --git a/tools/perf/util/bpf_off_cpu.c b/tools/perf/util/bpf_off_cpu.c index f289b7713598..7dbcb025da87 100644 --- a/tools/perf/util/bpf_off_cpu.c +++ b/tools/perf/util/bpf_off_cpu.c @@ -78,6 +78,7 @@ static void off_cpu_start(void *arg) u8 val = 1; skel->bss->has_task = 1; + skel->bss->uses_tgid = 1; fd = bpf_map__fd(skel->maps.task_filter); pid = perf_thread_map__pid(evlist->core.threads, 0); bpf_map_update_elem(fd, &pid, &val, BPF_ANY); diff --git a/tools/perf/util/bpf_skel/off_cpu.bpf.c b/tools/perf/util/bpf_skel/off_cpu.bpf.c index cc6d7fd55118..143a8b7acf87 100644 --- a/tools/perf/util/bpf_skel/off_cpu.bpf.c +++ b/tools/perf/util/bpf_skel/off_cpu.bpf.c @@ -85,6 +85,7 @@ int enabled = 0; int has_cpu = 0; int has_task = 0; int has_cgroup = 0; +int uses_tgid = 0; const volatile bool has_prev_state = false; const volatile bool needs_cgroup = false; @@ -144,7 +145,12 @@ static inline int can_record(struct task_struct *t, int state) if (has_task) { __u8 *ok; - __u32 pid = t->pid; + __u32 pid; + + if (uses_tgid) + pid = t->tgid; + else + pid = t->pid; ok = bpf_map_lookup_elem(&task_filter, &pid); if (!ok) |