From: Arnaldo Carvalho de Melo <acme@ghostprotocols.net>
To: Namhyung Kim <namhyung@kernel.org>
Cc: Peter Zijlstra <a.p.zijlstra@chello.nl>,
Paul Mackerras <paulus@samba.org>, Ingo Molnar <mingo@kernel.org>,
Namhyung Kim <namhyung.kim@lge.com>,
LKML <linux-kernel@vger.kernel.org>, Jiri Olsa <jolsa@redhat.com>,
David Ahern <dsahern@gmail.com>,
Stephane Eranian <eranian@google.com>,
Andi Kleen <andi@firstfloor.org>,
Pekka Enberg <penberg@kernel.org>,
Frederic Weisbecker <fweisbec@gmail.com>
Subject: Re: [PATCH 2/3] perf tools: Record sampling time for each entry
Date: Mon, 2 Dec 2013 15:49:05 -0300 [thread overview]
Message-ID: <20131202184905.GA14254@ghostprotocols.net> (raw)
In-Reply-To: <1385996264.1710.26.camel@leonhard>
Em Mon, Dec 02, 2013 at 11:57:44PM +0900, Namhyung Kim escreveu:
> 2013-12-02 (월), 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@lge.com>
> > >
> > > 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
next prev parent reply other threads:[~2013-12-02 18:49 UTC|newest]
Thread overview: 26+ messages / expand[flat|nested] mbox.gz Atom feed top
2013-12-02 6:53 [RFC 0/3] perf tools: Show time info (v1) Namhyung Kim
2013-12-02 6:53 ` [PATCH 1/3] perf tools: Record total sampling time Namhyung Kim
2013-12-02 12:45 ` Ingo Molnar
2013-12-02 12:57 ` Ingo Molnar
2013-12-02 15:43 ` Namhyung Kim
2013-12-02 16:36 ` Ingo Molnar
2013-12-02 20:24 ` Arnaldo Carvalho de Melo
2013-12-03 5:44 ` Namhyung Kim
2013-12-03 14:30 ` David Ahern
2013-12-04 10:00 ` Ingo Molnar
2013-12-04 10:02 ` Ingo Molnar
2013-12-03 5:33 ` Namhyung Kim
2013-12-02 15:05 ` Namhyung Kim
2013-12-02 18:51 ` Arnaldo Carvalho de Melo
2013-12-02 6:53 ` [PATCH 2/3] perf tools: Record sampling time for each entry Namhyung Kim
2013-12-02 12:39 ` Arnaldo Carvalho de Melo
2013-12-02 14:57 ` Namhyung Kim
2013-12-02 18:49 ` Arnaldo Carvalho de Melo [this message]
2013-12-03 4:33 ` Namhyung Kim
2013-12-02 6:53 ` [PATCH 3/3] perf report: Add --show-time-info option Namhyung Kim
2013-12-02 12:33 ` Arnaldo Carvalho de Melo
2013-12-02 14:38 ` Namhyung Kim
2013-12-02 9:35 ` [RFC 0/3] perf tools: Show time info (v1) Pekka Enberg
2013-12-03 2:28 ` Namhyung Kim
2013-12-02 17:04 ` Andi Kleen
2013-12-03 2:34 ` Namhyung Kim
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