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SubjectRe: [PATCH 0/4] perf tools: New comm infrastructure
Em Tue, Sep 17, 2013 at 02:54:22PM +0900, Namhyung Kim escreveu:
> Hi Ingo,
>
> On Sat, 14 Sep 2013 08:11:49 +0200, Ingo Molnar wrote:
> > * Frederic Weisbecker <fweisbec@gmail.com> wrote:
> >> My patches and Namhyung's should improve the comm situation a lot but we
> >> can't do much miracle. The only way would be perhaps to be able to limit
> >> the deepness of the callchain branches.
> >>
> >> Now may be we can find other big contention point in perf. It's possible
> >> we also have some endless loop somewhere.
> >
> > Well, it was the 100,000+ step linear list walk that was causing 90% of
> > the slowness here. Namhyung's patch should dramatically improve that. I
> > guess time for someone to post a combined tree so that it can be tested
> > all together?
>
> I pushed combined tree to 'perf/callchain-v2' branch in my tree
>
> git://git.kernel.org/pub/scm/linux/kernel/git/namhyung/linux-perf.git

But you did it for some old tree, as I tried running it now and since my
big perf.data file has PERF_RECORD_MMAP2 records, I can't try it with
your branch, working on cherry picking those changesets, since a plain
rebase didn't work.

- Arnaldo

>
> Please note that I also pushed other versions (v[1-3]). The v1 is my
> previous rbtree conversion patch, v2 adds Frederic's new comm
> infrastructure series on top and v3 adds my revised patch to refer
> current comm [1] on top of v2.
>
> I did my own test again among them. Test data is 400MB perf.data file
> created by parallel kernel build.
>
> $ ls -lh perf.data.big
> -rw-------. 1 namhyung namhyung 400M Sep 9 10:21 perf.data.big
>
> For more precise result, I changed cpufreq governor to 'performance'
>
> # echo performance > /sys/devices/system/cpu/cpu3/cpufreq/scaling_governor
>
> and run perf report on the cpu.
>
> $ taskset -c 3 time -p perf --no-pager report --stdio -i perf.data.big > /dev/null
>
> I ran it multiple times for each case and the results did not vary much.
>
> baseline v1 v2 v3
> ----------------------------------------------------------
> real 380.17 12.63 10.02 9.03
> user 378.86 11.95 9.66 8.69
> sys 0.70 0.65 0.33 0.34
>
>
> I also tried to cache latest result and reuse it when adding a callchain
> (in callchain_append() function) but it only hits ~5% and did not help
> the performance.
>
> Thanks,
> Namhyung
>
>
> [1] https://lkml.org/lkml/2013/9/16/565


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