Messages in this thread | | | Date | Fri, 17 Jun 2022 14:53:48 +0200 | From | Peter Zijlstra <> | Subject | Re: [PATCH v4] perf/core: Add a new read format to get a number of lost samples |
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On Thu, Jun 16, 2022 at 11:06:23AM -0700, Namhyung Kim wrote: > 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> > ---
Looks OK I suppose. Bit sad to get an unconditional atomic on the lost path, but then again, we shouldn't be hitting that in the first place.
Thanks!
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