linux-kernel - Re: [PATCH] perf tools: Fix to put caller above callee in children mode

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Date:   Tue, 23 May 2017 09:30:18 +0200
From:   Jiri Olsa <jolsa@...hat.com>
To:     Namhyung Kim <namhyung@...nel.org>
Cc:     Arnaldo Carvalho de Melo <acme@...nel.org>,
        Ingo Molnar <mingo@...nel.org>,
        Peter Zijlstra <a.p.zijlstra@...llo.nl>,
        Jiri Olsa <jolsa@...nel.org>,
        LKML <linux-kernel@...r.kernel.org>, kernel-team@....com,
        Frederic Weisbecker <fweisbec@...il.com>,
        Milian Wolff <milian.wolff@...b.com>
Subject: Re: [PATCH] perf tools: Fix to put caller above callee in children
 mode

On Mon, May 22, 2017 at 09:50:29PM +0900, Namhyung Kim wrote:
> The __hpp__sort_acc() sorts entries using callchain depth in order to
> put callers above in children mode.  But it assumed the callchain order
> was callee-first.  Now default (for children) is caller-first so the
> order of entries is reverted.
> 
> For example, consider following case.
> 
>   $ perf report --no-children
>   ..l
>   # Overhead  Command  Shared Object        Symbol
>   # ........  .......  ...................  ..........................
>   #
>       99.44%  a.out    a.out                [.] main
>               |
>               ---main
>                  __libc_start_main
>                  _start
> 
> Then children mode should show 'start' above '__libc_start_main' since
> it's the caller (parent) of the __libc_start_main.  But it's reversed:
> 
>   # Children      Self  Command  Shared Object    Symbol
>   # ........  ........  .......  ...............  .....................
>   #
>       99.61%     0.00%  a.out    libc-2.25.so     [.] __libc_start_main
>       99.61%     0.00%  a.out    a.out            [.] _start
>       99.54%    99.44%  a.out    a.out            [.] main
> 
> This patch fixes it.
> 
>   # Children      Self  Command  Shared Object    Symbol
>   # ........  ........  .......  ...............  .....................
>   #
>       99.61%     0.00%  a.out    a.out            [.] _start
>       99.61%     0.00%  a.out    libc-2.25.so     [.] __libc_start_main
>       99.54%    99.44%  a.out    a.out            [.] main
> 
> Cc: Frederic Weisbecker <fweisbec@...il.com>
> Cc: Milian Wolff <milian.wolff@...b.com>
> Signed-off-by: Namhyung Kim <namhyung@...nel.org>

Acked-by: Jiri Olsa <jolsa@...nel.org>

thanks,
jirka