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From:   Yang Jihong <yangjihong1@huawei.com>
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        <jolsa@kernel.org>, <namhyung@kernel.org>, <irogers@google.com>,
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CC:     <yangjihong1@huawei.com>
Subject: [PATCH v8 0/6] perf record: Track sideband events for all CPUs when tracing selected CPUs
Date:   Mon, 4 Sep 2023 02:33:34 +0000
Message-ID: <20230904023340.12707-1-yangjihong1@huawei.com>
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User space tasks can migrate between CPUs, track sideband events for all
CPUs.

The specific scenarios are as follows:

         CPU0                                 CPU1
  perf record -C 0 start
                              taskA starts to be created and executed
                                -> PERF_RECORD_COMM and PERF_RECORD_MMAP
                                   events only deliver to CPU1
                              ......
                                |
                          migrate to CPU0
                                |
  Running on CPU0    <----------/
  ...

  perf record -C 0 stop

Now perf samples the PC of taskA. However, perf does not record the
PERF_RECORD_COMM and PERF_RECORD_COMM events of taskA.
Therefore, the comm and symbols of taskA cannot be parsed.

The sys_perf_event_open invoked is as follows:

  # perf --debug verbose=3 record -e cpu-clock -C 1 true
  <SNIP>
  Opening: cpu-clock
  ------------------------------------------------------------
  perf_event_attr:
    type                             1 (PERF_TYPE_SOFTWARE)
    size                             136
    config                           0 (PERF_COUNT_SW_CPU_CLOCK)
    { sample_period, sample_freq }   4000
    sample_type                      IP|TID|TIME|CPU|PERIOD|IDENTIFIER
    read_format                      ID|LOST
    disabled                         1
    inherit                          1
    freq                             1
    sample_id_all                    1
    exclude_guest                    1
  ------------------------------------------------------------
  sys_perf_event_open: pid -1  cpu 1  group_fd -1  flags 0x8 = 5
  Opening: dummy:u
  ------------------------------------------------------------
  perf_event_attr:
    type                             1 (PERF_TYPE_SOFTWARE)
    size                             136
    config                           0x9 (PERF_COUNT_SW_DUMMY)
    { sample_period, sample_freq }   1
    sample_type                      IP|TID|TIME|CPU|IDENTIFIER
    read_format                      ID|LOST
    inherit                          1
    exclude_kernel                   1
    exclude_hv                       1
    mmap                             1
    comm                             1
    task                             1
    sample_id_all                    1
    exclude_guest                    1
    mmap2                            1
    comm_exec                        1
    ksymbol                          1
    bpf_event                        1
  ------------------------------------------------------------
  sys_perf_event_open: pid -1  cpu 0  group_fd -1  flags 0x8 = 6
  sys_perf_event_open: pid -1  cpu 1  group_fd -1  flags 0x8 = 7
  sys_perf_event_open: pid -1  cpu 2  group_fd -1  flags 0x8 = 9
  sys_perf_event_open: pid -1  cpu 3  group_fd -1  flags 0x8 = 10
  sys_perf_event_open: pid -1  cpu 4  group_fd -1  flags 0x8 = 11
  sys_perf_event_open: pid -1  cpu 5  group_fd -1  flags 0x8 = 12
  sys_perf_event_open: pid -1  cpu 6  group_fd -1  flags 0x8 = 13
  sys_perf_event_open: pid -1  cpu 7  group_fd -1  flags 0x8 = 14
  <SNIP>

Changes since_v7:
 - The condition for requiring system_wide sideband is changed to
   "as long as a non-dummy event exists" (patch4).
 - Modify the corresponding test case to record only dummy event (patch6).
 - Thanks to tested-by tag from Ravi, but because the solution is modified,
   the tested-by tag of Ravi is not added to this version.

Changes since_v6:
 - Patch1:
    1. No change.
    2. Keep Acked-by tag from Adrian.
 - Patch2:
    1. Update commit message as suggested by Ian.
    2. Keep Acked-by tag from Adrian because code is not modified.
 - Patch3:
    1. Update comment as suggested by Ian.
    2. Merge original patch5 ("perf test: Update base-record & system-wide-dummy attr") as suggested by Ian.
    3. Only merge commit, keep Acked-by tag from Adrian.
 - Patch4:
    1. No change. Because Adrian recommends not changing the function name.
    2. Keep Acked-by tag from Adrian.
 - Patch5:
    1. Add cleanup on trap function as suggested by Ian.
    2. Remove Tested-by tag from Adrian because the script is modified.
 - Patch6:
    1. Add Reviewed-by tag from Ian.

Changes since_v5:
 - No code changes.
 - Detailed commit message of patch3.
 - Add Acked-by and Tested-by tags from Adrian Hunter.

Changes since_v4:
 - Simplify check code for record__tracking_system_wide().
 - Add perf attr test result to commit message for patch 7.

Changes since_v3:
 - Check fall_kernel, all_user, and dummy or exclude_user when determining
   whether system wide is required.

Changes since_v2:
 - Rename record_tracking.sh to record_sideband.sh in tools/perf/tests/shell.
 - Remove "perf evlist: Skip dummy event sample_type check for evlist_config" patch.
 - Add opts->all_kernel check in record__config_tracking_events().
 - Add perf_event_attr test for record selected CPUs exclude_user.
 - Update base-record & system-wide-dummy sample_type attr expected values for test-record-C0.

Changes since v1:
 - Add perf_evlist__go_system_wide() via internal/evlist.h instead of
   exporting perf_evlist__propagate_maps().
 - Use evlist__add_aux_dummy() instead of evlist__add_dummy() in
   evlist__findnew_tracking_event().
 - Add a parameter in evlist__findnew_tracking_event() to deal with
   system_wide inside.
 - Add sideband for all CPUs when tracing selected CPUs comments on
   the perf record man page.
 - Use "sideband events" instead of "tracking events".
 - Adjust the patches Sequence.
 - Add patch5 to skip dummy event sample_type check for evlist_config.
 - Add patch6 to update system-wide-dummy attr values for perf test.

Yang Jihong (6):
  perf evlist: Add perf_evlist__go_system_wide() helper
  perf evlist: Add evlist__findnew_tracking_event() helper
  perf record: Move setting tracking events before
    record__init_thread_masks()
  perf record: Track sideband events for all CPUs when tracing selected
    CPUs
  perf test: Add test case for record sideband events
  perf test: Add perf_event_attr test for record selected CPUs
    exclude_user

Yang Jihong (6):
  perf evlist: Add perf_evlist__go_system_wide() helper
  perf evlist: Add evlist__findnew_tracking_event() helper
  perf record: Move setting tracking events before
    record__init_thread_masks()
  perf record: Track sideband events for all CPUs when tracing selected
    CPUs
  perf test: Add test case for record sideband events
  perf test: Add perf_event_attr test for record dummy event

 tools/lib/perf/evlist.c                    |  9 +++
 tools/lib/perf/include/internal/evlist.h   |  2 +
 tools/perf/Documentation/perf-record.txt   |  3 +
 tools/perf/builtin-record.c                | 92 +++++++++++++++-------
 tools/perf/tests/attr/system-wide-dummy    | 14 ++--
 tools/perf/tests/attr/test-record-C0       |  4 +-
 tools/perf/tests/attr/test-record-dummy-C0 | 55 +++++++++++++
 tools/perf/tests/shell/record_sideband.sh  | 58 ++++++++++++++
 tools/perf/util/evlist.c                   | 18 +++++
 tools/perf/util/evlist.h                   |  1 +
 10 files changed, 221 insertions(+), 35 deletions(-)
 create mode 100644 tools/perf/tests/attr/test-record-dummy-C0
 create mode 100755 tools/perf/tests/shell/record_sideband.sh

-- 
2.30.GIT