Re: [PATCH v4 1/3] perf: Use monotonic clock as a source for timestamps

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 <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?

Pawel