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

From: Jiri Olsa
Date: Fri Apr 18 2014 - 05:35:47 EST


On Fri, Apr 18, 2014 at 09:55:25AM +0200, Ingo Molnar wrote:
>
> * Ingo Molnar <mingo@xxxxxxxxxx> wrote:
>
> >
> > * Jiri Olsa <jolsa@xxxxxxxxxx> 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 :-)
>

yep, I should have put it in here as well.. also the current
libdw unwind time on this workload is 26 seconds.. 10 more
seconds to go ;-)

jirka
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