Messages in this thread | | | Date | Thu, 11 Jan 2018 12:10:01 +0100 | From | Jiri Olsa <> | Subject | Re: [RESEND PATCH V2 3/4] perf/x86/intel: drain PEBS buffer in event read |
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On Wed, Jan 10, 2018 at 09:31:56AM -0500, Liang, Kan wrote: > > > 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.
hum, but the PEBS drain is specific just for PERF_X86_EVENT_AUTO_RELOAD events, right?
wrt readability maybe you could add function like: bool pebs_drain_before_read(struct perf_event *event) { return event->hw.flags & PERF_X86_EVENT_AUTO_RELOAD; }
thanks, jirka
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