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

From: Arnaldo Carvalho de Melo
Date: Mon Nov 14 2016 - 09:31:06 EST


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