Re: [PATCH 2/3] perf tools: Record sampling time for each entry

From: Arnaldo Carvalho de Melo
Date: Mon Dec 02 2013 - 13:49:21 EST


Em Mon, Dec 02, 2013 at 11:57:44PM +0900, Namhyung Kim escreveu:
> 2013-12-02 (ì), 09:39 -0300, Arnaldo Carvalho de Melo:
> > Em Mon, Dec 02, 2013 at 03:53:18PM +0900, Namhyung Kim escreveu:
> > > From: Namhyung Kim <namhyung.kim@xxxxxxx>
> > >
> > > Calculate elapsed time for each sample and record it. The elapsed
> > > time is a diff between current sample->time and previous sample->time
> > > which was saved for each evsel and cpu.
> >
> > Can you elaborate on why this is interesting to have? What meaning can
> > one get from the sample->time - prev_sample->time?
> >
> > We need clearer changelogs...
>
> Sorry about that.. how about this?
>
> Sometimes users might want see a relation between value and time of a
> sample. And the time itself is a very important information to have.
> As the sample->period value is a diff of counter values between samples
> it might make sense to add time-diff between samples into a hist entry.
>
> To do that, calculate elapsed time for each sample and record it. The
> elapsed time is the diff between current sample->time and previous
> sample->time which was saved for each evsel.

Much better! Thanks, and please consider adding this to the man page as
well, in a followup patch.

I'll add the above explanation to the patch, that, as I could read seems
to not have had any nak, right?

- Arnaldo
--
To unsubscribe from this list: send the line "unsubscribe linux-kernel" in
the body of a message to majordomo@xxxxxxxxxxxxxxx
More majordomo info at http://vger.kernel.org/majordomo-info.html
Please read the FAQ at http://www.tux.org/lkml/