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Message-ID: <20150323233026.GF2782@sejong>
Date: Tue, 24 Mar 2015 08:30:26 +0900
From: Namhyung Kim <namhyung@...nel.org>
To: David Ahern <dsahern@...il.com>
Cc: Ingo Molnar <mingo@...nel.org>,
Arnaldo Carvalho de Melo <acme@...nel.org>,
Peter Zijlstra <a.p.zijlstra@...llo.nl>,
Jiri Olsa <jolsa@...hat.com>,
LKML <linux-kernel@...r.kernel.org>,
Frederic Weisbecker <fweisbec@...il.com>,
Stephane Eranian <eranian@...gle.com>
Subject: Re: [RFC/PATCH] perf record: Save build-id of DSO in callchains
Hi David,
On Mon, Mar 23, 2015 at 07:44:37AM -0600, David Ahern wrote:
> On 3/23/15 2:18 AM, Namhyung Kim wrote:
> >>Just curious, could you try to measure the performance impact of this
> >>change?
> >
> > $ time perf record --call-graph dwarf -o kbuild.xxx -a -- sleep 30
> > [ perf record: Woken up 34674 times to write data ]
> > [ perf record: Captured and wrote 9538.729 MB kbuild.xxx (1211997 samples) ]
> >
> > real 0m32.244s
> > user 0m1.097s
> > sys 0m8.997s
> >
> > $ time perf record --call-graph dwarf -o kbuild.yyy --buildid-callchain -a -- sleep 30
> > [ perf record: Woken up 40902 times to write data ]
> > [ perf record: Captured and wrote 11208.500 MB kbuild.yyy (1433922 samples) ]
> >
> > real 2m21.695s
> > user 1m33.127s
> > sys 0m22.077s
> >
>
> How many CPUs and processes?
I was running kbuild with allyesconfig on 12-cpu box.
Thanks,
Namhyung
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