linux-kernel - Re: [RFC][PATCH 7/7] perf/annotate: Add branch stack / basic block information

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Message-ID: <20160908165914.GR5871@two.firstfloor.org>
Date:   Thu, 8 Sep 2016 09:59:15 -0700
From:   Andi Kleen <andi@...stfloor.org>
To:     Stephane Eranian <eranian@...gle.com>
Cc:     Arnaldo Carvalho de Melo <acme@...nel.org>,
        Peter Zijlstra <peterz@...radead.org>,
        Ingo Molnar <mingo@...nel.org>,
        LKML <linux-kernel@...r.kernel.org>,
        Andi Kleen <andi@...stfloor.org>, Jiri Olsa <jolsa@...nel.org>,
        Linus Torvalds <torvalds@...ux-foundation.org>,
        David Carrillo-Cisneros <davidcc@...gle.com>,
        Alexander Shishkin <alexander.shishkin@...ux.intel.com>,
        Namhyung Kim <namhyung@...nel.org>,
        "Liang, Kan" <kan.liang@...el.com>,
        Anshuman Khandual <khandual@...ux.vnet.ibm.com>,
        yao.jin@...el.com
Subject: Re: [RFC][PATCH 7/7] perf/annotate: Add branch stack / basic block
 information

On Thu, Sep 08, 2016 at 09:43:53AM -0700, Stephane Eranian wrote:
> Hi,
> 
> On Thu, Sep 8, 2016 at 9:18 AM, Arnaldo Carvalho de Melo
> <acme@...nel.org> wrote:
> >
> > Em Fri, Jul 08, 2016 at 06:36:32PM +0200, Peter Zijlstra escreveu:
> > > On Fri, Jul 08, 2016 at 06:27:33PM +0200, Peter Zijlstra wrote:
> > >
> > > > I've been thinking of filtering all targets and branches that are
> > > > smaller than 0.1% in order to avoid this, but so far I've just been
> > > > ignoring these things.
> > >
> > > Like so... seems to 'work'.
> >
> > So I merged this one with 7/7 and this is the result, screenshot to
> > capture the colors:
> >
> >   http://vger.kernel.org/~acme/perf/annotate_basic_blocks.png
> >
> > Please let me know if I should go ahead and push with the combined
> > patch, that is now at:
> >
> > https://git.kernel.org/cgit/linux/kernel/git/acme/linux.git/commit/?h=perf/annotate_basic_blocks&id=baf41a43fa439ac534d21e41882a7858d5cee1e5
> >
> > git://git.kernel.org/pub/scm/linux/kernel/git/acme/linux.git perf/annotate_basic_blocks
> >
> > Is that ok?
> >
> I like the idea and yes, branch stack can be used for this, but I have
> a hard time understanding the colored output.
> What is the explanation for the color changes?
> How do I interpret the percentages in the comments of the assembly:
> -54.50% (p: 42%)
> Why not have dedicated columns before the assembly with proper column headers?

Yes columns with headers are better. Jin Yao has been looking at this and already has
some patches.

-Andi