linux-kernel - Re: [PATCH v4 0/6] perf report: Show branch flags/cycles in --branch-history callgraph view

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Date:   Mon, 14 Nov 2016 11:30:56 -0300
From:   Arnaldo Carvalho de Melo <acme@...nel.org>
To:     Andi Kleen <andi@...stfloor.org>
Cc:     Jin Yao <yao.jin@...ux.intel.com>, jolsa@...nel.org,
        Linux-kernel@...r.kernel.org, ak@...ux.intel.com,
        kan.liang@...el.com
Subject: Re: [PATCH v4 0/6] perf report: Show branch flags/cycles in
 --branch-history callgraph view

Em Mon, Oct 31, 2016 at 09:19:48AM +0800, Jin Yao escreveu:
> v4: Update according to Andi's comments. The requirement is not displaying
>     the number of removed loops. It needs to display the average number of
>     iterations. It computes out the number of iterations by counting
>     the removed loops. 
> 
> v3: 1. Display the count for tsx abort, remove the abort percentage.
> 
>     2. Since the branch history code has a loop detection that removes
>        small loops in util/machine.c:remove_loops(). It would be nice to
>        note how many loops were removed. So it adds the note on some
>        callchain entries.
> 
> v2: Just a rebase to Arnaldo's perf/core branch, no functional changes.

Andi, are you ok with this now? Can I have your Acked-by or Tested-by?

Thanks,

- Arnaldo
 
> Initial post
> 
> perf record -g -b ...
> perf report --branch-history
> 
> Currently it only shows the branches from the LBR in the callgraph view.
> It would be useful to annotate branch predictions and TSX aborts and
> also timed LBR cycles also in the callgraph view.
> 
> This would allow a quick overview where branch predictions are and how
> costly basic blocks are.
> 
> For example:
> 
> # Overhead  Source:Line                  Symbol                       Shared Object      Predicted  Abort  Cycles
> # ........  ...........................  ...........................  .................  .........  .....  ......
> #
>     38.25%  div.c:45                     [.] main                     div                97.6%      0      3
>             |
>             ---main div.c:42 (cycles:2)
>                compute_flag div.c:28 (cycles:2)
>                compute_flag div.c:27 (cycles:1)
>                rand rand.c:28 (cycles:1)
>                rand rand.c:28 (cycles:1)
>                __random random.c:298 (cycles:1)
>                __random random.c:297 (cycles:1)
>                __random random.c:295 (cycles:1)
>                __random random.c:295 (cycles:1)
>                __random random.c:295 (cycles:1)
>                __random random.c:295 (cycles:9)
>                |
>                |--36.73%--__random_r random_r.c:392 (cycles:9)
>                |          __random_r random_r.c:357 (cycles:1)
>                |          __random random.c:293 (cycles:1)
>                |          __random random.c:293 (cycles:1)
>                |          __random random.c:291 (cycles:1)
>                |          __random random.c:291 (cycles:1)
>                |          __random random.c:291 (cycles:1)
>                |          __random random.c:288 (cycles:1)
>                |          rand rand.c:27 (cycles:1)
>                |          rand rand.c:26 (cycles:1)
>                |          rand@plt +4194304 (cycles:1)
>                |          rand@plt +4194304 (cycles:1)
>                |          compute_flag div.c:25 (cycles:1)
>                |          compute_flag div.c:22 (cycles:1)
>                |          main div.c:40 (cycles:1)
>                |          main div.c:40 (cycles:16)
>                |          main div.c:39 (cycles:16)
>                |          |
>                |          |--29.93%--main div.c:39 (predicted:50.6%, cycles:1, iterations:18)
>                |          |          main div.c:44 (predicted:50.6%, cycles:1)
>                |          |          |
>                |          |           --22.69%--main div.c:42 (cycles:2, iterations:17)
>                |          |                     compute_flag div.c:28 (cycles:2)
>                |          |                     |
>                |          |                      --10.52%--compute_flag div.c:27 (cycles:1)
>                |          |                                rand rand.c:28 (cycles:1)
> 
> Jin Yao (6):
>   perf report: Add branch flag to callchain cursor node
>   perf report: Create a symbol_conf flag for showing branch flag
>     counting
>   perf report: Caculate and return the branch flag counting
>   perf report: Show branch info in callchain entry for stdio mode
>   perf report: Show branch info in callchain entry for browser mode
>   perf report: Display columns Predicted/Abort/Cycles in
>     --branch-history
> 
>  tools/perf/Documentation/perf-report.txt |   9 ++
>  tools/perf/builtin-report.c              |   9 +-
>  tools/perf/ui/browsers/hists.c           |  20 ++-
>  tools/perf/ui/stdio/hist.c               |  35 +++++-
>  tools/perf/util/callchain.c              | 203 ++++++++++++++++++++++++++++++-
>  tools/perf/util/callchain.h              |  22 +++-
>  tools/perf/util/hist.c                   |   3 +
>  tools/perf/util/hist.h                   |   3 +
>  tools/perf/util/machine.c                |  82 ++++++++++---
>  tools/perf/util/sort.c                   | 113 ++++++++++++++++-
>  tools/perf/util/sort.h                   |   3 +
>  tools/perf/util/symbol.h                 |   1 +
>  12 files changed, 476 insertions(+), 27 deletions(-)
> 
> -- 
> 2.7.4