[PATCH v6 1/4] lib: add generic support for reading PMU events

[Tyler Retzlaff]

On Fri, Jan 20, 2023 at 12:39:12AM +0100, Tomasz Duszynski wrote:
> Add support for programming PMU counters and reading their values
> in runtime bypassing kernel completely.
> 
> This is especially useful in cases where CPU cores are isolated
> (nohz_full) i.e run dedicated tasks. In such cases one cannot use
> standard perf utility without sacrificing latency and performance.
> 
> Signed-off-by: Tomasz Duszynski <tduszynski at marvell.com>
> ---
>  MAINTAINERS                            |   5 +
>  app/test/meson.build                   |   4 +
>  app/test/test_pmu.c                    |  42 +++
>  doc/api/doxy-api-index.md              |   3 +-
>  doc/api/doxy-api.conf.in               |   1 +
>  doc/guides/prog_guide/profile_app.rst  |   8 +
>  doc/guides/rel_notes/release_23_03.rst |   7 +
>  lib/meson.build                        |   1 +
>  lib/pmu/meson.build                    |  13 +
>  lib/pmu/pmu_private.h                  |  29 ++
>  lib/pmu/rte_pmu.c                      | 436 +++++++++++++++++++++++++
>  lib/pmu/rte_pmu.h                      | 206 ++++++++++++
>  lib/pmu/version.map                    |  19 ++
>  13 files changed, 773 insertions(+), 1 deletion(-)
>  create mode 100644 app/test/test_pmu.c
>  create mode 100644 lib/pmu/meson.build
>  create mode 100644 lib/pmu/pmu_private.h
>  create mode 100644 lib/pmu/rte_pmu.c
>  create mode 100644 lib/pmu/rte_pmu.h
>  create mode 100644 lib/pmu/version.map
> 
> diff --git a/MAINTAINERS b/MAINTAINERS
> index 9a0f416d2e..9f13eafd95 100644
> --- a/MAINTAINERS
> +++ b/MAINTAINERS
> @@ -1697,6 +1697,11 @@ M: Nithin Dabilpuram <ndabilpuram at marvell.com>
>  M: Pavan Nikhilesh <pbhagavatula at marvell.com>
>  F: lib/node/
>  
> +PMU - EXPERIMENTAL
> +M: Tomasz Duszynski <tduszynski at marvell.com>
> +F: lib/pmu/
> +F: app/test/test_pmu*
> +
>  
>  Test Applications
>  -----------------
> diff --git a/app/test/meson.build b/app/test/meson.build
> index f34d19e3c3..b2c2a618b1 100644
> --- a/app/test/meson.build
> +++ b/app/test/meson.build
> @@ -360,6 +360,10 @@ if dpdk_conf.has('RTE_LIB_METRICS')
>      test_sources += ['test_metrics.c']
>      fast_tests += [['metrics_autotest', true, true]]
>  endif
> +if is_linux
> +    test_sources += ['test_pmu.c']
> +    fast_tests += [['pmu_autotest', true, true]]
> +endif

traditionally we don't conditionally include tests at the meson.build
level, instead we run all tests and have them skip when executed for
unsupported exec environments.

you can take a look at test_eventdev.c as an example for a test that is
skipped on windows, i'm sure it could be adapted to skip on freebsd if
you aren't supporting it.