Messages in this thread | | | Date | Thu, 28 Mar 2013 16:52:29 +0100 | From | Robert Richter <> | Subject | Re: [RFC PATCH 0/3] Perf persistent events |
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On 18.03.13 09:46:38, Ingo Molnar wrote: > > * Namhyung Kim <namhyung@kernel.org> wrote: > > > So my question is how can an user know which persistent events are > > available in her system? > > I think we need VFS enumeration for that: directories give a high level a > structure (allowing things like per user contexts) while readdir will give > list of specific persistent buffer contexts. > > Sensible naming convention would be needed to make things easy to discover > and list - and for active buffers to not be forgotten about. > > cgroups or a new 'eventfs' filesystem would be an option.
An option would be to attach the persistent events to a hosting pmu (e.g. 'ras' in this case) and provide the events via sysfs as already done by other pmus:
/sys/bus/event_source/devices/ras/events/ /sys/bus/event_source/devices/ras/events/mce_record ...
perf tools work then out-the-box with -e ras/mce_record/.
The event is selected by the 'ras' pmu and then routed to the original pmu that might be e.g. 'tracepoint'. So we attach each persistent event to a 'virtual' pmu which does the grouping in the perf sysfs and the forwarding to its actual pmu.
-Robert
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