Re: [PATCH 1/3] perf callchain: Convert children list to rbtree

From: Ingo Molnar
Date: Tue Sep 10 2013 - 06:26:07 EST



* Jiri Olsa <jolsa@xxxxxxxxxx> wrote:

> On Tue, Sep 10, 2013 at 05:24:16PM +0900, Namhyung Kim wrote:
> > From: Namhyung Kim <namhyung.kim@xxxxxxx>
> >
> > Current collapse stage has a scalability problem which can be
> > reproduced easily with parallel kernel build. This is because it
> > needs to traverse every children of callchain linearly during the
> > collapse/merge stage. Convert it to rbtree reduced the overhead
> > significantly.
> >
> > On my 400MB perf.data file which recorded with make -j32 kernel build:
>
>
> nice!!!

Nice indeed!

> tried on 2.6 GB data file from kernel make -j64 and got report speed up
> from 'never' to 2m52.756s ;-)

It's still rather long though, unacceptable for everyday usage :-/

Frederic thought that we could reduce minimize collapsing to begin with.

Frederic, could you outline that in more detail please?

Thanks,

Ingo
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