Messages in this thread | | | Subject | Re: [RESEND PATCH V2 3/4] perf/x86/intel: drain PEBS buffer in event read | From | "Liang, Kan" <> | Date | Wed, 10 Jan 2018 09:31:56 -0500 |
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On 1/10/2018 5:39 AM, Jiri Olsa wrote: > On Mon, Jan 08, 2018 at 07:15:15AM -0800, kan.liang@intel.com wrote: >> From: Kan Liang <kan.liang@linux.intel.com> >> >> When the PEBS interrupt threshold is larger than one, there is no way to >> get exact auto-reload times and value needed for event update unless >> flush the PEBS buffer. >> >> Drain the PEBS buffer in event read when large PEBS is enabled. >> >> For the threshold is one, even auto-reload is enabled, it doesn't need >> to be specially handled. Because auto-reload is only effect when event >> overflow. There is no overflow in event read. >> >> Signed-off-by: Kan Liang <kan.liang@linux.intel.com> >> --- >> arch/x86/events/intel/core.c | 9 +++++++++ >> arch/x86/events/intel/ds.c | 10 ++++++++++ >> arch/x86/events/perf_event.h | 2 ++ >> 3 files changed, 21 insertions(+) >> >> diff --git a/arch/x86/events/intel/core.c b/arch/x86/events/intel/core.c >> index 09c26a4..bdc35f8 100644 >> --- a/arch/x86/events/intel/core.c >> +++ b/arch/x86/events/intel/core.c >> @@ -2060,6 +2060,14 @@ static void intel_pmu_del_event(struct perf_event *event) >> intel_pmu_pebs_del(event); >> } >> >> +static void intel_pmu_read_event(struct perf_event *event) >> +{ >> + if (event->attr.precise_ip) >> + return intel_pmu_pebs_read(event); > > check for (event->hw.flags & PERF_X86_EVENT_AUTO_RELOAD) > would be more accurate? >
It will narrow down the events. But considering the readability, I think it would be better to use precise_ip.The exposed functions in ds.c should be generic functions for all PEBS events, not specific case. I think _AUTO_RELOAD looks too specific.
Thanks, Kan
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