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From: kan.liang@linux.intel.com
To: acme@kernel.org, namhyung@kernel.org, irogers@google.com,
	peterz@infradead.org, mingo@kernel.org,
	linux-kernel@vger.kernel.org, linux-perf-users@vger.kernel.org
Cc: adrian.hunter@intel.com, ak@linux.intel.com, eranian@google.com,
	Kan Liang <kan.liang@linux.intel.com>
Subject: [PATCH V2 0/9] Support branch counters in block annotation
Date: Thu,  8 Aug 2024 12:33:15 -0700	[thread overview]
Message-ID: <20240808193324.2027665-1-kan.liang@linux.intel.com> (raw)

From: Kan Liang <kan.liang@linux.intel.com>

Changes since V1:
- Add Acked-by from Namhyung for patch 1 and 2.
- Use array to replace pointer to store the abbr name. (Patch 5)
  (Namhyung)
- Add -v to print the value like "A=<n>,B=<n>", rather than histogram.
  (Patch 6) (Namhyung)

The branch counters logging (A.K.A LBR event logging) introduces a
per-counter indication of precise event occurrences in LBRs. It can
provide a means to attribute exposed retirement latency to combinations
of events across a block of instructions. It also provides a means of
attributing Timed LBR latencies to events.

The kernel support and basic perf tool support have been merged.
https://lore.kernel.org/lkml/20231025201626.3000228-1-kan.liang@linux.intel.com/

This series is to provide advanced perf tool support via adding the
branch counters information in block annotation. It can further
facilitate the analysis of branch blocks.

The patch 1 and 2 are to fix two existing issues of --total-cycles and
the branch counters feature.

The patch 3-9 are the advanced perf tool support.

Here are some examples.

perf annotation:

$perf record -e "{branch-instructions:ppp,branch-misses}:S" -j any,counter
$perf report  --total-cycles --stdio

 # To display the perf.data header info, please use --header/--header-only options.
 #
 #
 # Total Lost Samples: 0
 #
 # Samples: 1M of events 'anon group { branch-instructions:ppp, branch-misses }'
 # Event count (approx.): 1610046
 #
 # Branch counter abbr list:
 # branch-instructions:ppp = A
 # branch-misses = B
 # '-' No event occurs
 # '+' Event occurrences may be lost due to branch counter saturated
 #
 # Sampled Cycles%  Sampled Cycles  Avg Cycles%  Avg Cycles          Branch Counter [Program Block Range]
 # ...............  ..............  ...........  ..........  ......................  ..
 #
           57.55%            2.5M        0.00%           3             |A   |-   |                 ...
           25.27%            1.1M        0.00%           2             |AA  |-   |                 ...
           15.61%          667.2K        0.00%           1             |A   |-   |                 ...
            0.16%            6.9K        0.81%         575             |A   |-   |                 ...
            0.16%            6.8K        1.38%         977             |AA  |-   |                 ...
            0.16%            6.8K        0.04%          28             |AA  |B   |                 ...
            0.15%            6.6K        1.33%         946             |A   |-   |                 ...
            0.11%            4.5K        0.06%          46             |AAA+|-   |                 ...

With -v applied,
$perf report  --total-cycles --stdio -v

 # Sampled Cycles%  Sampled Cycles  Avg Cycles%  Avg Cycles          Branch Counter [Program Block Range]
 # ...............  ..............  ...........  ..........  ......................  ..................
 #
           57.55%            2.5M        0.00%           3               A=1 ,B=-                  ...
           25.27%            1.1M        0.00%           2               A=2 ,B=-                  ...
           15.61%          667.2K        0.00%           1               A=1 ,B=-                  ...
            0.16%            6.9K        0.81%         575               A=1 ,B=-                  ...
            0.16%            6.8K        1.38%         977               A=2 ,B=-                  ...
            0.16%            6.8K        0.04%          28               A=2 ,B=1                  ...
            0.15%            6.6K        1.33%         946               A=1 ,B=-                  ...
            0.11%            4.5K        0.06%          46               A=3+,B=-                  ...

(The below output is in the TUI mode. Users can press 'B' to display
the Branch counter abbr list.)

Samples: 1M of events 'anon group { branch-instructions:ppp, branch-misses }',
4000 Hz, Event count (approx.):
f3  /home/sdp/test/tchain_edit [Percent: local period]
Percent       │ IPC Cycle       Branch Counter (Average IPC: 1.39, IPC Coverage: 29.4%)
              │                                     0000000000401755 <f3>:
  0.00   0.00 │                                       endbr64
              │                                       push    %rbp
              │                                       mov     %rsp,%rbp
              │                                       movl    $0x0,-0x4(%rbp)
  0.00   0.00 │1.33     3          |A   |-   |      ↓ jmp     25
 11.03  11.03 │                                 11:   mov     -0x4(%rbp),%eax
              │                                       and     $0x1,%eax
              │                                       test    %eax,%eax
 17.13  17.13 │2.41     1          |A   |-   |      ↓ je      21
              │                                       addl    $0x1,-0x4(%rbp)
 21.84  21.84 │2.22     2          |AA  |-   |      ↓ jmp     25
 17.13  17.13 │                                 21:   addl    $0x1,-0x4(%rbp)
 21.84  21.84 │                                 25:   cmpl    $0x270f,-0x4(%rbp)
 11.03  11.03 │0.61     3          |A   |-   |      ↑ jle     11
              │                                       nop
              │                                       pop     %rbp
  0.00   0.00 │0.24    20          |AA  |B   |      ← ret

perf script:

$perf script -F +brstackinsn,+brcntr

 # Branch counter abbr list:
 # branch-instructions:ppp = A
 # branch-misses = B
 # '-' No event occurs
 # '+' Event occurrences may be lost due to branch counter saturated
     tchain_edit  332203 3366329.405674:      53030 branch-instructions:ppp:            401781 f3+0x2c (home/sdp/test/tchain_edit)
        f3+31:
        0000000000401774        insn: eb 04                     br_cntr: AA     # PRED 5 cycles [5]
        000000000040177a        insn: 81 7d fc 0f 27 00 00
        0000000000401781        insn: 7e e3                     br_cntr: A      # PRED 1 cycles [6] 2.00 IPC
        0000000000401766        insn: 8b 45 fc
        0000000000401769        insn: 83 e0 01
        000000000040176c        insn: 85 c0

$perf script -F +brstackinsn,+brcntr -v

     tchain_edit  332203 3366329.405674:      53030 branch-instructions:ppp:            401781 f3+0x2c (/home/sdp/test/tchain_edit)
        f3+31:
        0000000000401774        insn: eb 04                     br_cntr: branch-instructions:ppp 2 branch-misses 0      # PRED 5 cycles [5]
        000000000040177a        insn: 81 7d fc 0f 27 00 00
        0000000000401781        insn: 7e e3                     br_cntr: branch-instructions:ppp 1 branch-misses 0      # PRED 1 cycles [6] 2.00 IPC
        0000000000401766        insn: 8b 45 fc
        0000000000401769        insn: 83 e0 01
        000000000040176c        insn: 85 c0

Kan Liang (9):
  perf report: Fix --total-cycles --stdio output error
  perf report: Remove the first overflow check for branch counters
  perf evlist: Save branch counters information
  perf annotate: Save branch counters for each block
  perf evsel: Assign abbr name for the branch counter events
  perf report: Display the branch counter histogram
  perf annotate: Display the branch counter histogram
  perf script: Add branch counters
  perf test: Add new test cases for the branch counter feature

 tools/perf/Documentation/perf-report.txt |   1 +
 tools/perf/Documentation/perf-script.txt |   2 +-
 tools/perf/builtin-annotate.c            |  13 +-
 tools/perf/builtin-diff.c                |   8 +-
 tools/perf/builtin-report.c              |  25 ++-
 tools/perf/builtin-script.c              |  69 ++++++-
 tools/perf/builtin-top.c                 |   4 +-
 tools/perf/tests/shell/record.sh         |  17 +-
 tools/perf/ui/browsers/annotate.c        |  18 +-
 tools/perf/ui/browsers/hists.c           |  18 +-
 tools/perf/util/annotate.c               | 253 +++++++++++++++++++++--
 tools/perf/util/annotate.h               |  24 ++-
 tools/perf/util/block-info.c             |  66 +++++-
 tools/perf/util/block-info.h             |   8 +-
 tools/perf/util/branch.h                 |   1 +
 tools/perf/util/disasm.c                 |   1 +
 tools/perf/util/evlist.c                 |  68 ++++++
 tools/perf/util/evlist.h                 |   2 +
 tools/perf/util/evsel.c                  |  15 +-
 tools/perf/util/evsel.h                  |  14 ++
 tools/perf/util/hist.c                   |   5 +-
 tools/perf/util/hist.h                   |   2 +-
 tools/perf/util/machine.c                |   3 +
 23 files changed, 567 insertions(+), 70 deletions(-)

-- 
2.38.1


             reply	other threads:[~2024-08-08 19:32 UTC|newest]

Thread overview: 15+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2024-08-08 19:33 kan.liang [this message]
2024-08-08 19:33 ` [PATCH V2 1/9] perf report: Fix --total-cycles --stdio output error kan.liang
2024-08-08 19:33 ` [PATCH V2 2/9] perf report: Remove the first overflow check for branch counters kan.liang
2024-08-08 19:33 ` [PATCH V2 3/9] perf evlist: Save branch counters information kan.liang
2024-08-08 19:33 ` [PATCH V2 4/9] perf annotate: Save branch counters for each block kan.liang
2024-08-08 19:33 ` [PATCH V2 5/9] perf evsel: Assign abbr name for the branch counter events kan.liang
2024-08-08 19:33 ` [PATCH V2 6/9] perf report: Display the branch counter histogram kan.liang
2024-08-08 19:33 ` [PATCH V2 7/9] perf annotate: " kan.liang
2024-08-08 19:33 ` [PATCH V2 8/9] perf script: Add branch counters kan.liang
2024-08-08 19:33 ` [PATCH V2 9/9] perf test: Add new test cases for the branch counter feature kan.liang
2024-08-08 20:27 ` [PATCH V2 0/9] Support branch counters in block annotation Andi Kleen
2024-08-12 19:39 ` Namhyung Kim
2024-08-12 20:13   ` Arnaldo Carvalho de Melo
2024-08-13 15:15     ` Liang, Kan
2024-08-13 15:17       ` Arnaldo Carvalho de Melo

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