linux-kernel - Re: [PATCH v2 2/6] perf report: Caculate and return the branch counting in callchain

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Message-ID: <CACbG3095a0Y84O_JPB3HKVyKTBTwdg660o8bSs7JgcDmj=XDSQ@mail.gmail.com>
Date:   Thu, 20 Oct 2016 12:06:22 -0500
From:   Nilay Vaish <nilayvaish@...il.com>
To:     Andi Kleen <ak@...ux.intel.com>
Cc:     Jin Yao <yao.jin@...ux.intel.com>,
        Arnaldo Carvalho de Melo <acme@...nel.org>,
        Jiri Olsa <jolsa@...nel.org>,
        Linux Kernel list <Linux-kernel@...r.kernel.org>,
        kan.liang@...el.com
Subject: Re: [PATCH v2 2/6] perf report: Caculate and return the branch
 counting in callchain

On 20 October 2016 at 11:48, Andi Kleen <ak@...ux.intel.com> wrote:
> On Thu, Oct 20, 2016 at 11:41:11AM -0500, Nilay Vaish wrote:
>> On 19 October 2016 at 17:01, Jin Yao <yao.jin@...ux.intel.com> wrote:
>> > diff --git a/tools/perf/util/callchain.h b/tools/perf/util/callchain.h
>> > index 40ecf25..4f6bf6c 100644
>> > --- a/tools/perf/util/callchain.h
>> > +++ b/tools/perf/util/callchain.h
>> > @@ -115,6 +115,10 @@ struct callchain_list {
>> >                 bool            unfolded;
>> >                 bool            has_children;
>> >         };
>> > +       u64                     branch_count;
>> > +       u64                     predicted_count;
>> > +       u64                     abort_count;
>>
>> Can you explain what abort count is?  It seems you are referring to
>> miss-speculated branches.  If that is the case, I would prefer that we
>> replace abort by miss_speculated or miss_predicted.
>
> abort refers to TSX aborts. It has nothing to do with branch
> mispredictions.

OK, I am more confused now.  Are you predicting some quantity related
to transactions?  Why would you divide abort count by branch count?
Further, I just looked at patch 6/6.  It has the following text:

+ Also show with some branch flags that can be:
+ - Predicted: display the average percentage of predicated branches.
+     (predicated number / total number)
+ - Abort: display the average percentage of abort branches.
+ (abort number /total number)
+ - Cycles: cycles in basic block.


I think there is inconsistency between what you are suggesting and
what the patch has.

--
Nilay