Messages in this thread | | | From | "Liang, Kan" <> | Subject | Re: [PATCH 4/9] perf/x86/intel: Support hardware TopDown metrics | Date | Tue, 28 May 2019 14:24:56 -0400 |
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On 5/28/2019 9:48 AM, Peter Zijlstra wrote: > On Tue, May 21, 2019 at 02:40:50PM -0700, kan.liang@linux.intel.com wrote: >> diff --git a/include/linux/perf_event.h b/include/linux/perf_event.h >> index b980b9e95d2a..0d7081434d1d 100644 >> --- a/include/linux/perf_event.h >> +++ b/include/linux/perf_event.h >> @@ -133,6 +133,11 @@ struct hw_perf_event { >> >> struct hw_perf_event_extra extra_reg; >> struct hw_perf_event_extra branch_reg; >> + >> + u64 saved_metric; >> + u64 saved_slots; >> + u64 last_slots; >> + u64 last_metric; > > This is really sad, and I'm thinking much of that really isn't needed > anyway, due to how you're not using some of the other fields.
If we don't cache the value, we have to update all metrics events when reading any metrics event. I think that could bring high overhead.
Thanks, Kan > >> }; >> struct { /* software */ >> struct hrtimer hrtimer; >> -- >> 2.14.5 >>
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