Re: [PATCH v4 1/3] perf: Use monotonic clock as a source for timestamps
From: Pawel Moll <hidden>
Date: 2014-12-11 13:39:34
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On Thu, 2014-11-27 at 15:05 +0000, Pawel Moll wrote:
On Thu, 2014-11-06 at 16:51 +0000, Pawel Moll wrote:quoted
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 <redacted>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?
It's been another two weeks... How about getting it queued for v3.20 then? Pawel