Re: [PATCH v2] perf/core: Add a new read format to get a number of lost samples

Namhyung Kim
2021-10-15T06:29:16Z

Ping!

On Wed, Sep 22, 2021 at 12:34 PM Namhyung Kim <namhyung@kernel.org> wrote:
>
> Hi Peter,
>
> On Fri, Sep 10, 2021 at 3:40 PM Namhyung Kim <namhyung@kernel.org> wrote:
> >
> > On Fri, Sep 10, 2021 at 2:42 PM Jiri Olsa <jolsa@redhat.com> wrote:
> > >
> > > On Wed, Sep 08, 2021 at 10:24:20AM -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.
> > >
> > > hi,
> > > looks good.. will there be some tools/perf change using this?
> >
> > Sure, I'll work on the userspace part after this is merged.
> > I'm thinking about adding LOST_SAMPLES records at the end
> > of the data section as if they came from the kernel.
>
> Can I get your feedback?
>
> Thanks,
> Namhyung