Messages in this thread Patch in this message | | | Date | Tue, 4 Nov 2014 08:23:08 +0100 | From | Peter Zijlstra <> | Subject | Re: [PATCH v3 1/3] perf: Use monotonic clock as a source for timestamps |
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On Tue, Nov 04, 2014 at 12:28:36AM +0000, Pawel Moll wrote:
> +int sysctl_perf_sample_time_clk_id = CLOCK_MONOTONIC;
const ?
> /* > * perf samples are done in some very critical code paths (NMIs). > * If they take too much CPU time, the system can lock up and not > @@ -324,7 +326,7 @@ extern __weak const char *perf_pmu_name(void) > > static inline u64 perf_clock(void) > { > - return local_clock(); > + return ktime_get_mono_fast_ns(); > }
Do we maybe want to make it boot-time switchable back to local_clock for people with bad systems and or backwards compat issues?
Everybody using Core2 and older will very much not want to have this unless they've got a very good reason for wanting it.
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