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Subject: Re: [PATCH v6 0/7] perf record: Track sideband events for all CPUs
 when tracing selected CPUs
To:     Arnaldo Carvalho de Melo <acme@kernel.org>
References: <20230821012734.18241-1-yangjihong1@huawei.com>
From:   Yang Jihong <yangjihong1@huawei.com>
CC:     <peterz@infradead.org>, <mingo@redhat.com>, <mark.rutland@arm.com>,
        <alexander.shishkin@linux.intel.com>, <jolsa@kernel.org>,
        <namhyung@kernel.org>, <irogers@google.com>,
        <adrian.hunter@intel.com>, <kan.liang@linux.intel.com>,
        <james.clark@arm.com>, <tmricht@linux.ibm.com>,
        <ak@linux.intel.com>, <anshuman.khandual@arm.com>,
        <linux-kernel@vger.kernel.org>, <linux-perf-users@vger.kernel.org>
Message-ID: <3a069f1b-4bf8-f2f9-00fc-3e69c8b6cfcf@huawei.com>
Date:   Wed, 23 Aug 2023 09:17:56 +0800
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Hi Arnaldo,

Can you consider applying this patchset ?
Please let me know if there is anything that needs to be fixed.

Yang,
Thanks

On 2023/8/21 9:27, Yang Jihong wrote:
> 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_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 (7):
>    perf evlist: Add perf_evlist__go_system_wide() helper
>    perf evlist: Add evlist__findnew_tracking_event() helper
>    perf record: Move setting dummy tracking before
>      record__init_thread_masks()
>    perf record: Track sideband events for all CPUs when tracing selected
>      CPUs
>    perf test: Update base-record & system-wide-dummy attr expected values
>      for test-record-C0
>    perf test: Add test case for record sideband events
>    perf test: Add perf_event_attr test for record selected CPUs
>      exclude_user
> 
>   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                   | 106 +++++++++++++-----
>   tools/perf/tests/attr/system-wide-dummy       |  14 ++-
>   tools/perf/tests/attr/test-record-C0          |   4 +-
>   .../perf/tests/attr/test-record-C0-all-kernel |  32 ++++++
>   tools/perf/tests/shell/record_sideband.sh     |  44 ++++++++
>   tools/perf/util/evlist.c                      |  18 +++
>   tools/perf/util/evlist.h                      |   1 +
>   10 files changed, 198 insertions(+), 35 deletions(-)
>   create mode 100644 tools/perf/tests/attr/test-record-C0-all-kernel
>   create mode 100755 tools/perf/tests/shell/record_sideband.sh
>