Re: [PATCH v6 0/5] Hwmon PMUs

[Namhyung Kim <namhyung@kernel.org>]

Hi Ian,

On Tue, Oct 22, 2024 at 11:06:18AM -0700, Ian Rogers wrote:
> Following the convention of the tool PMU, create a hwmon PMU that
> exposes hwmon data for reading. For example, the following shows
> reading the CPU temperature and 2 fan speeds alongside the uncore
> frequency:
> ```
> $ perf stat -e temp_cpu,fan1,hwmon_thinkpad/fan2/,tool/num_cpus_online/ -M UNCORE_FREQ -I 1000
>      1.001153138              52.00 'C   temp_cpu
>      1.001153138              2,588 rpm  fan1
>      1.001153138              2,482 rpm  hwmon_thinkpad/fan2/
>      1.001153138                  8      tool/num_cpus_online/
>      1.001153138      1,077,101,397      UNC_CLOCK.SOCKET                 #     1.08 UNCORE_FREQ
>      1.001153138      1,012,773,595      duration_time
> ...
> ```
> 
> Additional data on the hwmon events is in perf list:
> ```
> $ perf list
> ...
> hwmon:
> ...
>   temp_core_0 OR temp2
>        [Temperature in unit coretemp named Core 0. crit=100'C,max=100'C crit_alarm=0'C. Unit:
>         hwmon_coretemp]
> ...
> ```
> 
> v6: Add string.h #include for issue reported by kernel test robot.
> v5: Fix asan issue in parse_hwmon_filename caught by a TMA metric.
> v4: Drop merged patches 1 to 10. Separate adding the hwmon_pmu from
>     the update to perf_pmu to use it. Try to make source of literal
>     strings clearer via named #defines. Fix a number of GCC warnings.
> v3: Rebase, add Namhyung's acked-by to patches 1 to 10.
> v2: Address Namhyung's review feedback. Rebase dropping 4 patches
>     applied by Arnaldo, fix build breakage reported by Arnaldo.
> 
> Ian Rogers (5):
>   tools api io: Ensure line_len_out is always initialized
>   perf hwmon_pmu: Add a tool PMU exposing events from hwmon in sysfs
>   perf pmu: Add calls enabling the hwmon_pmu
>   perf test: Add hwmon "PMU" test
>   perf docs: Document tool and hwmon events

I think the patch 2 can be easily splitted into core and other parts
like dealing with aliases and units.  I believe it'd be helpful for
others (like me) to understand how it works.

Please take a look at 'perf/hwmon-pmu' branch in:

  https://git.kernel.org/pub/scm/linux/kernel/git/namhyung/linux-perf.git

Thanks,
Namhyung

> 
>  tools/lib/api/io.h                     |   1 +
>  tools/perf/Documentation/perf-list.txt |  15 +
>  tools/perf/tests/Build                 |   1 +
>  tools/perf/tests/builtin-test.c        |   1 +
>  tools/perf/tests/hwmon_pmu.c           | 243 ++++++++
>  tools/perf/tests/tests.h               |   1 +
>  tools/perf/util/Build                  |   1 +
>  tools/perf/util/evsel.c                |   9 +
>  tools/perf/util/hwmon_pmu.c            | 821 +++++++++++++++++++++++++
>  tools/perf/util/hwmon_pmu.h            | 154 +++++
>  tools/perf/util/pmu.c                  |  20 +
>  tools/perf/util/pmu.h                  |   2 +
>  tools/perf/util/pmus.c                 |   9 +
>  tools/perf/util/pmus.h                 |   3 +
>  14 files changed, 1281 insertions(+)
>  create mode 100644 tools/perf/tests/hwmon_pmu.c
>  create mode 100644 tools/perf/util/hwmon_pmu.c
>  create mode 100644 tools/perf/util/hwmon_pmu.h
> 
> -- 
> 2.47.0.163.g1226f6d8fa-goog
>