Messages in this thread | | | Subject | Re: [PATCH v4 1/3] perf: Use monotonic clock as a source for timestamps | From | Pawel Moll <> | Date | Thu, 27 Nov 2014 15:05:50 +0000 |
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On Thu, 2014-11-06 at 16:51 +0000, Pawel Moll wrote: > Until now, perf framework never defined the meaning of the timestamps > captured as PERF_SAMPLE_TIME sample type. The values were obtaining > from local (sched) clock, which is unavailable in userspace. This made > it impossible to correlate perf data with any other events. Other > tracing solutions have the source configurable (ftrace) or just share > a common time domain between kernel and userspace (LTTng). > > Follow the trend by using monotonic clock, which is readily available > as POSIX CLOCK_MONOTONIC. > > Also add a sysctl "perf_sample_time_clk_id" attribute which can be used > by the user to obtain the clk_id to be used with POSIX clock API (eg. > clock_gettime()) to obtain a time value comparable with perf samples. > > Old behaviour can be restored by using "perf_use_local_clock" kernel > parameter. > > Signed-off-by: Pawel Moll <pawel.moll@arm.com>
It's been 3 weeks without any negative feedback (no feedback at all, but I take the optimistic view :-)...
How about queuing at least this patch alone for the incoming merge window? Or at least getting it into -next, with the view at 3.20?
Pawel
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