linux-kernel - Re: [PATCH 01/28] perf tools: Insert filtered entries to hists also

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Date:	Wed, 8 Jan 2014 17:22:53 +0100
From:	Jiri Olsa <jolsa@...hat.com>
To:	Arnaldo Carvalho de Melo <acme@...stprotocols.net>
Cc:	Namhyung Kim <namhyung@...nel.org>,
	Peter Zijlstra <a.p.zijlstra@...llo.nl>,
	Paul Mackerras <paulus@...ba.org>,
	Ingo Molnar <mingo@...nel.org>,
	Namhyung Kim <namhyung.kim@....com>,
	LKML <linux-kernel@...r.kernel.org>,
	Arun Sharma <asharma@...com>,
	Frederic Weisbecker <fweisbec@...il.com>,
	Rodrigo Campos <rodrigo@...g.com.ar>
Subject: Re: [PATCH 01/28] perf tools: Insert filtered entries to hists also

On Wed, Jan 08, 2014 at 09:41:13AM -0300, Arnaldo Carvalho de Melo wrote:
> Em Wed, Jan 08, 2014 at 05:46:06PM +0900, Namhyung Kim escreveu:
> > Currently if a sample was filtered by command line option, it just
> > dropped.  But this affects final output in that the percentage can be
> > different since the filtered entries were not included to the total.
> > 
> > For example, if an original output looked like below:
> 
> Humm, if one says that he/she is interested on just samples for a and b,
> the current behaviour will state how many of the filtered samples are
> for a and b, which is valid.
> 
>  I bet the number of samples will reflect that as well, but you filtered
> it out, yes, it stays there, so the percentages are relative to the
> number of samples.
> 
> So I think this change in behaviour is wrong, no?
> 
hi,
haven't checked the implementation yet, but it kind of does
what I'd expect for symbol filtering:

perf report
...
 22.00%  yes  libc-2.17.so       [.] __strlen_sse2
 11.79%  yes  libc-2.17.so       [.] fputs_unlocked
  9.65%  yes  libc-2.17.so       [.] __GI___mempcpy
  1.91%  yes  yes                [.] fputs_unlocked@plt
...

search (press '/') for fputs_unlocked (with Namhyung's change):
 11.79%  yes  libc-2.17.so  [.] fputs_unlocked
  1.91%  yes  yes           [.] fputs_unlocked@plt

while the current one shows:
 86.08%  yes  libc-2.17.so  [.] fputs_unlocked
 13.92%  yes  yes           [.] fputs_unlocked@plt

which annoys me when searching for 'invisible' symbol
within tons of others.. I had to do that grep thing
you showed.

I'd like to have the Namhyung's change behaviour as default,
but I'll be happy with some switch as well ;-)

thanks,
jirka
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