Re: [PATCH 1/3] perf tools: Record total sampling time

[Arnaldo Carvalho de Melo <acme@ghostprotocols.net>]

Em Tue, Dec 03, 2013 at 12:05:49AM +0900, Namhyung Kim escreveu:
> Hi Ingo,
> 
> 2013-12-02 (월), 13:45 +0100, Ingo Molnar:
> > * Namhyung Kim <namhyung@kernel.org> wrote:
> > 
> > > From: Namhyung Kim <namhyung.kim@lge.com>
> > > 
> > > It's sometimes useful to see total sampling or elapsed time with
> > > normal performance result.  To do that, record first and last sample
> > > time for each evsel and to display it in the header (--stdio only for
> > > now).
> > > 
> > >   $ perf record -a sleep 1
> > >   $ perf report --stdio
> > >   ...
> > >   # Samples: 4K of event 'cycles'
> > >   # Event count (approx.): 4087481688
> > >   # Total sampling time  : 1.001260 (sec)
> > 
> > Btw., would it make sense to output it using the 'perf stat' print-out 
> > machinery?
> > 
> > If the 'count' of every event sampled is saved in the perf.data, 
> > including elapsed time, at the beginning and at the end, then all 
> > information is there to output things in perf stat style.
> 
> Yeah, it'd be great if we can share same code in the end.

I guess we'll basically just process all samples, accumulating stuff
where the builtin-stat code finds them, in struct perf_evsel, then just
hand it to that code.

- Arnaldo