Re: [RFC/PATCHSET 00/17] perf tools: Add support for hierachy view (v2)

From: Namhyung Kim
Date: Tue Jan 19 2016 - 20:36:51 EST


Hi Andi,

On Wed, Jan 20, 2016 at 02:11:00AM +0100, Andi Kleen wrote:
> On Wed, Jan 20, 2016 at 09:56:47AM +0900, Namhyung Kim wrote:
> > On Tue, Jan 19, 2016 at 07:24:49PM -0300, Arnaldo Carvalho de Melo wrote:
> > > Em Tue, Jan 19, 2016 at 11:12:04PM +0100, Andi Kleen escreveu:
> > > > It only considers the hits on the leaf function, but doesn't hide
> > > > the individual call chains leading to that function which are below
> > > > the limit.
> > > >
> > > > So if you have a lot of different cold callers you still end up
> > > > with far too much output.
> >
> > Could you please be more specific? Let me try with an example..
> >
> > $ perf report
> > ...
> > + 1.00% perf perf some_function
> > some_function
> > - common_caller
> > - 0.6% caller1
> > + 0.4% caller1_1
> > + 0.2% caller1_2
> > + 0.3% caller2
> > + 0.1% caller3
> >
> > In this case, do you want this?
> >
> > $ perf report --percent-limit 0.5
> > ...
> > + 1.00% perf perf some_function
> > some_function
> > - common_caller
> > - 0.6% caller1
>
> Right. Only call chains whose total percentage is larger than the limit.

So in this case, caller1_1 and caller1_2 are both under the percent
limit but after they merged at caller1, it should be shown. Look like
a reasonable result. I'll add it into my TODO list. :)

Btw, is it all you wanted to say? Is there any other case for trouble
(wrt callchain percent limit)?

Thanks,
Namhyung