Messages in this thread | | | From | Andy Lutomirski <> | Date | Mon, 3 Nov 2014 16:58:32 -0800 | Subject | Re: [PATCH v3 0/3] perf: User/kernel time correlation and event generation |
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On Mon, Nov 3, 2014 at 4:28 PM, Pawel Moll <pawel.moll@arm.com> wrote: > From: Pawel Moll <mail@pawelmoll.com> > Thomas suggested solution which gets down to my original proposal for > sched/monotonic clock correlation - an additional sample type so events > can be "double stamped" using different clock sources providing > synchronisation points for later time approximation. I've just extended > the implementation with configuration value to select the clock source. > If the first patch (making perf timestamps monotonic) gets accepted, > there will be no immediate need for this one, but I'd like to gain some > feedback anyway. >
I have nothing intelligent to add to the potentional Thomas/Ingo showdown, but I do have a related thought. :)
If you're going to add double-stamped packets, can you also add a syscall to read multiple clocks at once, atomically? Or can you otherwise add a non-perf mechanism to get at this data?
Because the realtime to monotonic offset is really quite useful for things like this, and it seems silly to make people actually open a perf_event to get at it.
--Andy
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