RE: [PATCH v8 1/4] lib: add generic support for reading PMU events

[Ruifeng Wang <Ruifeng.Wang@arm.com>]

> -----Original Message-----
> From: Tomasz Duszynski <tduszynski@marvell.com>
> Sent: Thursday, February 2, 2023 5:44 PM
> To: dev@dpdk.org; thomas@monjalon.net; Tomasz Duszynski <tduszynski@marvell.com>
> Cc: roretzla@linux.microsoft.com; Ruifeng Wang <Ruifeng.Wang@arm.com>;
> bruce.richardson@intel.com; jerinj@marvell.com; mattias.ronnblom@ericsson.com;
> mb@smartsharesystems.com; zhoumin@loongson.cn
> Subject: [PATCH v8 1/4] lib: add generic support for reading PMU events
> 
> 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@marvell.com>
> Acked-by: Morten Brørup <mb@smartsharesystems.com>
> ---
>  MAINTAINERS                            |   5 +
>  app/test/meson.build                   |   1 +
>  app/test/test_pmu.c                    |  55 +++
>  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 |   9 +
>  lib/meson.build                        |   1 +
>  lib/pmu/meson.build                    |  13 +
>  lib/pmu/pmu_private.h                  |  29 ++
>  lib/pmu/rte_pmu.c                      | 464 +++++++++++++++++++++++++
>  lib/pmu/rte_pmu.h                      | 205 +++++++++++
>  lib/pmu/version.map                    |  20 ++
>  13 files changed, 813 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
>
 
<snip>

> diff --git a/doc/guides/rel_notes/release_23_03.rst
> b/doc/guides/rel_notes/release_23_03.rst
> index 73f5d94e14..733541d56c 100644
> --- a/doc/guides/rel_notes/release_23_03.rst
> +++ b/doc/guides/rel_notes/release_23_03.rst
> @@ -55,10 +55,19 @@ New Features
>       Also, make sure to start the actual text at the margin.
>       =======================================================
> 
> +* **Added PMU library.**
> +
> +  Added a new PMU (performance measurement unit) library which allows

Overall looks good to me. Just a minor comment.
Should it be 'performance *monitoring* unit'?
I see the same terminology is used across architectures. It will be better if we align with that.

Thanks.

<snip>