linux-kernel - Re: [PATCH 2/2] perf callchain: Use global caching provided by libunwind

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Date:	Tue, 23 Sep 2014 21:53:43 +0900
From:	Namhyung Kim <namhyung@...nel.org>
To:	Jiri Olsa <jolsa@...hat.com>
Cc:	Arnaldo Carvalho de Melo <acme@...nel.org>,
	Peter Zijlstra <a.p.zijlstra@...llo.nl>,
	Ingo Molnar <mingo@...nel.org>,
	Paul Mackerras <paulus@...ba.org>,
	Namhyung Kim <namhyung.kim@....com>,
	LKML <linux-kernel@...r.kernel.org>,
	Jean Pihet <jean.pihet@...aro.org>,
	Arun Sharma <asharma@...com>
Subject: Re: [PATCH 2/2] perf callchain: Use global caching provided by libunwind

On Tue, Sep 23, 2014 at 9:28 PM, Jiri Olsa <jolsa@...hat.com> wrote:
> On Tue, Sep 23, 2014 at 03:30:28PM +0900, Namhyung Kim wrote:
>> The libunwind provides two caching policy which are global and
>> per-thread.  As perf unwinds callchains in a single thread, it'd
>> sufficient to use global caching.
>>
>> This speeds up my perf report from 14s to 7s on a ~260MB data file.
>> Although the output contains a slight difference (~0.01% in terms of
>> number of lines printed) on callchains which were not resolved.
>
> hum, the speedup is nice, but what was the diff output.. any example?
> The new version does not print some lines or different ones?

I don't have the result now - will post the diff when I go to the
office tomorrow.  But IIRC new version only adds new lines..

Thanks,
Namhyung
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