linux-kernel - Re: [RFC PATCH v1] perf Documentation: Describe the PMU naming convention

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Message-ID: <CAP-5=fXfUeuouJkW5uiB-6A6M9Ng86QzgNXZjO0C77oL4anWsA@mail.gmail.com>
Date: Tue, 14 May 2024 11:05:45 -0700
From: Ian Rogers <irogers@...gle.com>
To: Randy Dunlap <rdunlap@...radead.org>
Cc: Tuan Phan <tuanphan@...amperecomputing.com>, Robin Murphy <robin.murphy@....com>, 
	Thomas Richter <tmricht@...ux.ibm.com>, Bhaskara Budiredla <bbudiredla@...vell.com>, 
	Bharat Bhushan <bbhushan2@...vell.com>, Peter Zijlstra <peterz@...radead.org>, 
	Ingo Molnar <mingo@...hat.com>, Arnaldo Carvalho de Melo <acme@...nel.org>, Namhyung Kim <namhyung@...nel.org>, 
	Mark Rutland <mark.rutland@....com>, 
	Alexander Shishkin <alexander.shishkin@...ux.intel.com>, Jiri Olsa <jolsa@...nel.org>, 
	Adrian Hunter <adrian.hunter@...el.com>, Kan Liang <kan.liang@...ux.intel.com>, 
	James Clark <james.clark@....com>, Ravi Bangoria <ravi.bangoria@....com>, 
	linux-perf-users@...r.kernel.org, linux-kernel@...r.kernel.org, 
	Will Deacon <will@...nel.org>, Stephane Eranian <eranian@...gle.com>
Subject: Re: [RFC PATCH v1] perf Documentation: Describe the PMU naming convention

On Mon, May 13, 2024 at 10:40 PM Randy Dunlap <rdunlap@...radead.org> wrote:
>
> Hi,
>
> On 5/13/24 5:58 PM, Ian Rogers wrote:
> > It is an existing convention to use suffixes with PMU names. Try to
> > capture that convention so that future PMU devices may adhere to it.
> >
> > The name of the file and date within the file try to follow existing
> > conventions, particularly sysfs-bus-event_source-devices-events.
> > ---
> >  .../testing/sysfs-bus-event_source-devices    | 24 +++++++++++++++++++
> >  1 file changed, 24 insertions(+)
> >  create mode 100644 Documentation/ABI/testing/sysfs-bus-event_source-devices
> >
> > diff --git a/Documentation/ABI/testing/sysfs-bus-event_source-devices b/Documentation/ABI/testing/sysfs-bus-event_source-devices
> > new file mode 100644
> > index 000000000000..3f7e53e82de7
> > --- /dev/null
> > +++ b/Documentation/ABI/testing/sysfs-bus-event_source-devices
> > @@ -0,0 +1,24 @@
> > +What: /sys/bus/event_source/devices/<pmu>
> > +Date: 2014/02/24
> > +Contact:     Linux kernel mailing list <linux-kernel@...r.kernel.org>
> > +Description: Performance Monitoring Unit (<pmu>)
> > +
>
> Mostly looks good to me. I prefer a small change (below).
>
> > +             Each <pmu> directory, for a PMU device, is a name
> > +             optionally followed by an underscore and then either a
> > +             decimal or hexadecimal number. For example, cpu is a
> > +             PMU name without a suffix as is intel_bts,
> > +             uncore_imc_0 is a PMU name with a 0 numeric suffix,
> > +             ddr_pmu_87e1b0000000 is a PMU name with a hex
> > +             suffix. The hex suffix must be more than two
> > +             characters long to avoid ambiguity with PMUs like the
> > +             S390 cpum_cf.
> > +
> > +             Tools can treat PMUs with the same name that differ by
> > +             suffix as instances of the same PMU for the sake of,
> > +             for example, opening an event. For example, the PMUs
> > +             uncore_imc_free_running_0 and
> > +             uncore_imc_free_running_1 have an event data_read,
>
> s/,/;/
> or: s/,/./ and begin the next sentence with a capital letter.
>
> > +             opening the data_read event on a PMU specified as
> > +             uncore_imc_free_running should be treated as opening
> > +             the data_read event on PMU uncore_imc_free_running_0
> > +             and PMU uncore_imc_free_running_1.
>
> With that change, you may add:
>
> Reviewed-by: Randy Dunlap <rdunlap@...radead.org>
>
> thanks.

Thanks Randy, I'll leave this on the list to bake a little longer and
then send a v2 with your fixes.

Ian

> --
> #Randy
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