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From: Namhyung Kim <namhyung@kernel.org>
To: Milian Wolff <mail@milianw.de>
Cc: Arnaldo Carvalho de Melo <acme@kernel.org>,
	linux-perf-users <linux-perf-users@vger.kernel.org>
Subject: Re: Size of perf data files
Date: Thu, 27 Nov 2014 09:56:21 +0900	[thread overview]
Message-ID: <87oarto40a.fsf@sejong.aot.lge.com> (raw)
In-Reply-To: <1439400.fEBkspRaxp@milian-kdab2> (Milian Wolff's message of "Wed, 26 Nov 2014 19:11:01 +0100")

Hi Milian,

On Wed, 26 Nov 2014 19:11:01 +0100, Milian Wolff wrote:
> I tried this on a benchmark of mine:
>
> before:
> [ perf record: Woken up 196 times to write data ]
> [ perf record: Captured and wrote 48.860 MB perf.data (~2134707 samples) ]
>
> after, with dwarf,512
> [ perf record: Woken up 18 times to write data ]
> [ perf record: Captured and wrote 4.401 MB perf.data (~192268 samples) ]
>
> What confuses me though is the number of samples. When the workload is equal, 
> shouldn't the number of samples stay the same? Or what does this mean? The 
> resulting reports both look similar enough.

It's bogus - it just calculates the number of samples based on the file
size (with fixed sample size).  I think we should either show the correct
number as we post-process samples for build-id detection or simply
remove it.

Thanks,
Namhyung

  reply	other threads:[~2014-11-27  0:56 UTC|newest]

Thread overview: 12+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2014-11-26 12:47 Size of perf data files Milian Wolff
2014-11-26 16:06 ` Arnaldo Carvalho de Melo
2014-11-26 18:11   ` Milian Wolff
2014-11-27  0:56     ` Namhyung Kim [this message]
2014-11-27 13:19       ` Arnaldo Carvalho de Melo
2014-11-28  6:18         ` Namhyung Kim
2014-11-26 20:48 ` Andi Kleen
  -- strict thread matches above, loose matches on Subject: below --
2015-01-06  3:21 Yale Zhang
2015-01-06  5:39 ` Andi Kleen
2015-01-06 21:02   ` Yale Zhang
2015-01-06 21:29     ` Andi Kleen
2015-01-09  2:06     ` Frank Ch. Eigler

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