| Message ID | 20221028180128.3311491-5-namhyung@kernel.org (mailing list archive) |
|---|---|
| State | Not Applicable |
| Delegated to: | BPF |
| Headers | show |
| Series | None | expand |
diff --git a/tools/perf/util/lock-contention.h b/tools/perf/util/lock-contention.h index b8cb8830b7bc..e3c061b1795b 100644 --- a/tools/perf/util/lock-contention.h +++ b/tools/perf/util/lock-contention.h @@ -91,7 +91,7 @@ struct thread_stat { * Number of stack trace entries to skip when finding callers. * The first few entries belong to the locking implementation itself. */ -#define CONTENTION_STACK_SKIP 3 +#define CONTENTION_STACK_SKIP 4 /* * flags for lock:contention_begin
In most configurations, it works well with skipping 4 entries by default. If some systems still have 3 BPF internal stack frames, the next frame should be in a lock function which will be skipped later when it tries to find a caller. So increasing to 4 won't affect such systems too. With --stack-skip=0, I can see something like this: 24 49.84 us 7.41 us 2.08 us mutex bpf_prog_e1b85959d520446c_contention_begin+0x12e 0xffffffffc045040e bpf_prog_e1b85959d520446c_contention_begin+0x12e 0xffffffffc045040e bpf_prog_e1b85959d520446c_contention_begin+0x12e 0xffffffff82ea2071 bpf_trace_run2+0x51 0xffffffff82de775b __bpf_trace_contention_begin+0xb 0xffffffff82c02045 __mutex_lock+0x245 0xffffffff82c019e3 __mutex_lock_slowpath+0x13 0xffffffff82c019c0 mutex_lock+0x20 0xffffffff830a083c kernfs_iop_permission+0x2c Cc: Song Liu <song@kernel.org> Cc: bpf@vger.kernel.org Signed-off-by: Namhyung Kim <namhyung@kernel.org> --- tools/perf/util/lock-contention.h | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-)