Re: [PATCH 6/6][v3] perf: Document the ABI of perf sysfs entries

From: Jiri Olsa
Date: Thu Jan 17 2013 - 09:12:03 EST


On Wed, Jan 16, 2013 at 10:58:16AM -0800, Sukadev Bhattiprolu wrote:
> Jiri Olsa [jolsa@xxxxxxxxxx] wrote:
> | On Tue, Jan 15, 2013 at 03:57:59PM -0300, Arnaldo Carvalho de Melo wrote:
> | > Em Wed, Jan 09, 2013 at 05:07:03PM -0800, Sukadev Bhattiprolu escreveu:
> | > > [PATCH 6/6][v3] perf: Document the ABI of perf sysfs entries
> | > >
> | > > This patchset addes two new sets of files to sysfs:
> | > >
> | > > - generic and POWER-specific perf events in /sys/devices/cpu/events/
> | > > - perf event config format in /sys/devices/cpu/format/event
> | > >
> | > > Document the format of these files which would become part of the ABI.
> | > >
> | > > Changelog[v3]:
> | > > [Greg KH] Include ABI documentation.
> | >
> | > Jiri, can I have your ack on this one too?
> |
> | hm, we already already 'format' definition but in testing section
> | (and we are missing 'events' definition there.. my bad)
>
> I see that file now ! I have removed that documentation from my patch.
> |
> | anyway, after reading Documentation/ABI/README looks like we
> | should go for 'testing' section with this as well.. stable
> | seems scary at this point ;-)
>
> Agree.
>
> Here is the updated patch.
> ---
>
> This patchset addes two new sets of files to sysfs for POWER architecture.
>
> - perf event config format in /sys/devices/cpu/format/event
> - generic and POWER-specific perf events in /sys/devices/cpu/events/
>
> The format of the first file is already documented in:
>
> Documentation/ABI/testing/sysfs-bus-event_source-devices-format
>
> Document the format of the second set of files '/sys/devices/cpu/events/*'
> which would also become part of the ABI.
>
> Changelog[v3.1]:
> (small changes to this one patch).
> [Jiri Olsa]: Remove the documentation for the 'config format' file
> as it is already documented.
> [Jiri Olsa]: Move the documentation of 'events' also to 'testing/'
>
> Changelog[v3]:
> [Greg KH] Include ABI documentation.
>
> Signed-off-by: Sukadev Bhattiprolu <sukadev@xxxxxxxxxxxxxxxxxx>
> ---
> .../testing/sysfs-bus-event_source-devices-events | 58 ++++++++++++++++++++
> 1 files changed, 58 insertions(+), 0 deletions(-)
> delete mode 100644 Documentation/ABI/stable/sysfs-devices-cpu-events
> create mode 100644 Documentation/ABI/testing/sysfs-bus-event_source-devices-events
>
> diff --git a/Documentation/ABI/stable/sysfs-devices-cpu-events b/Documentation/ABI/stable/sysfs-devices-cpu-events
> deleted file mode 100644
> index e69de29..0000000
> diff --git a/Documentation/ABI/testing/sysfs-bus-event_source-devices-events b/Documentation/ABI/testing/sysfs-bus-event_source-devices-events
> new file mode 100644
> index 0000000..2c4081e
> --- /dev/null
> +++ b/Documentation/ABI/testing/sysfs-bus-event_source-devices-events
> @@ -0,0 +1,58 @@
> +What: /sys/devices/cpu/events/
> + /sys/devices/cpu/events/branch-misses
> + /sys/devices/cpu/events/cache-references
> + /sys/devices/cpu/events/cache-misses
> + /sys/devices/cpu/events/stalled-cycles-frontend
> + /sys/devices/cpu/events/branch-instructions
> + /sys/devices/cpu/events/stalled-cycles-backend
> + /sys/devices/cpu/events/instructions
> + /sys/devices/cpu/events/cpu-cycles
> +
> +Date: 2012/01/NN
> +
> +Contact: Linux kernel mailing list <linux-kernel@xxxxxxxxxxxxxxx>
> +
> +Description: Generic performance monitoring events
> +
> + A collection of performance monitoring events that may be
> + supported by many/most CPUs. These events can be monitored
> + using the 'perf(1)' tool.
> +
> + The contents of each file would look like:
> +
> + event=0xNNNN
> +
> + where 'N' is a hex digit and the number '0xNNNN' shows the
> + "raw code" for the perf event identified by the file's
> + "basename".

Maybe it'd worth to mention, that it does not need to be just 'event',
but anything from /sys/bus/event_source/devices/<dev>/format directory,
like

The can be multiple terms like 'event=0xNNNN' specified
and separated with comma. All available terms are located
in /sys/bus/event_source/devices/<dev>/format file.

Please feel free to rephrase or use proper English ;-)

otherwise it's ok,
jirka
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