linux-kernel - Re: [PATCH 0/3] perf tools: Speedup DWARF unwind

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Date:	Fri, 18 Apr 2014 09:55:25 +0200
From:	Ingo Molnar <mingo@...nel.org>
To:	Jiri Olsa <jolsa@...hat.com>
Cc:	linux-kernel@...r.kernel.org,
	Corey Ashford <cjashfor@...ux.vnet.ibm.com>,
	David Ahern <dsahern@...il.com>,
	Frederic Weisbecker <fweisbec@...il.com>,
	Namhyung Kim <namhyung@...nel.org>,
	Paul Mackerras <paulus@...ba.org>,
	Peter Zijlstra <a.p.zijlstra@...llo.nl>,
	Arnaldo Carvalho de Melo <acme@...stprotocols.net>,
	Jean Pihet <jean.pihet@...aro.org>
Subject: Re: [PATCH 0/3] perf tools: Speedup DWARF unwind


* Ingo Molnar <mingo@...nel.org> wrote:

> 
> * Jiri Olsa <jolsa@...hat.com> wrote:
> 
> > hi,
> > trying to speedup DWARF unwind report code by factoring
> > related code:
> >   - caching sample's registers access
> >   - keep dso data file descriptor open for the
> >     life of the dso object
> >   - replace dso cache code by mapping dso data file
> >     directly for the life of the dso object
> > 
> > The speedup is mainly for libunwind unwind. The libdw will benefit
> > mainly from cached registers access, because it handles dso data
> > accesses by itself.. and anyway it's still faster ;-).
> 
> Just curious: do you have any numbers about how much faster it got in 
> practice?

Oh, the numbers are all in the changelogs, never mind!

So in your test workload it went from 54.6 seconds to 36.7, a 48% 
speedup :-)

Thanks,

	Ingo
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