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Date: Mon, 11 Nov 2013 14:56:37 +0100
From: Ingo Molnar <mingo@kernel.org>
To: Frederic Weisbecker <fweisbec@gmail.com>
Cc: Namhyung Kim <namhyung@kernel.org>, Pekka Enberg <penberg@kernel.org>,
        Arnaldo Carvalho de Melo <acme@ghostprotocols.net>,
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        Rodrigo Campos <rodrigo@sdfg.com.ar>, Arun Sharma <asharma@fb.com>
Subject: Re: [RFC/PATCHSET 00/14] perf report: Add support to accumulate hist
 periods (v2)
Message-ID: <20131111135637.GD8781@gmail.com>
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* Frederic Weisbecker <fweisbec@gmail.com> wrote:

> On Mon, Nov 11, 2013 at 01:13:52PM +0100, Ingo Molnar wrote:
> > 
> > It's not an irrelevant feature at all! :-)
> > 
> > It's just that for any sort of longer profile it was pretty 
> > difficult/frustrating to use, which I think held back adoption.
> > 
> > That performance problem got fixed now by you and Namhyung, so I think 
> > we'll see even wider adoption of call-graph profiling...
> 
> Ah I see now. At the time Linus reported his issue, I had the feeling 
> his usecase was a bit "extreme", but I actually have no idea how far 
> perf can be used given that I'm mostly used to short benchmarks, 
> typically hackbench, perf bench sched messaging et al. Thing is I don't 
> use it enough for my real usecases :)

Well, it's a bit of a catch-22: if there are severe scalability problems 
for a usecase then people won't use it because they cannot use it. So 
developers should usually try to over-measure things and go for extreme 
uses and such.

Thanks,

	Ingo