diff options
| author | Namhyung Kim <namhyung@kernel.org> | 2022-06-16 11:06:23 -0700 |
|---|---|---|
| committer | Greg Kroah-Hartman <gregkh@linuxfoundation.org> | 2023-12-13 18:18:15 +0100 |
| commit | 84ca356ec859478a2524a1885fae4bf7de4003b1 (patch) | |
| tree | 20589efd5a809703e85c996cc662e2a8c039d95e /kernel/events/ring_buffer.c | |
| parent | 07bdb1bd24765a22a04e656d9bd292a1c17870f5 (diff) | |
perf/core: Add a new read format to get a number of lost samples
[ Upstream commit 119a784c81270eb88e573174ed2209225d646656 ]
Sometimes we want to know an accurate number of samples even if it's
lost. Currenlty PERF_RECORD_LOST is generated for a ring-buffer which
might be shared with other events. So it's hard to know per-event
lost count.
Add event->lost_samples field and PERF_FORMAT_LOST to retrieve it from
userspace.
Original-patch-by: Jiri Olsa <jolsa@redhat.com>
Signed-off-by: Namhyung Kim <namhyung@kernel.org>
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Link: https://lkml.kernel.org/r/20220616180623.1358843-1-namhyung@kernel.org
Stable-dep-of: 382c27f4ed28 ("perf: Fix perf_event_validate_size()")
Signed-off-by: Sasha Levin <sashal@kernel.org>
Diffstat (limited to 'kernel/events/ring_buffer.c')
| -rw-r--r-- | kernel/events/ring_buffer.c | 5 |
1 files changed, 4 insertions, 1 deletions
diff --git a/kernel/events/ring_buffer.c b/kernel/events/ring_buffer.c index fb3edb2f8ac9..679cc87b40f4 100644 --- a/kernel/events/ring_buffer.c +++ b/kernel/events/ring_buffer.c @@ -171,8 +171,10 @@ __perf_output_begin(struct perf_output_handle *handle, goto out; if (unlikely(rb->paused)) { - if (rb->nr_pages) + if (rb->nr_pages) { local_inc(&rb->lost); + atomic64_inc(&event->lost_samples); + } goto out; } @@ -255,6 +257,7 @@ __perf_output_begin(struct perf_output_handle *handle, fail: local_inc(&rb->lost); + atomic64_inc(&event->lost_samples); perf_output_put_handle(handle); out: rcu_read_unlock(); |