Commit 5bee2cc6 authored Feb 12, 2018 by Kan Liang Committed by Ingo Molnar Mar 09, 2018

perf/x86/intel/ds: Introduce ->read() function for auto-reload events and...


perf/x86/intel/ds: Introduce ->read() function for auto-reload events and flush the PEBS buffer there

There is no way to get exact auto-reload times and values which are needed
for event updates unless we flush the PEBS buffer.

Introduce intel_pmu_auto_reload_read() to drain the PEBS buffer for
auto reload event. To prevent races with the hardware, we can only
call drain_pebs() when the PMU is disabled.

Signed-off-by: Kan Liang <kan.liang@linux.intel.com>
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Cc: Alexander Shishkin <alexander.shishkin@linux.intel.com>
Cc: Arnaldo Carvalho de Melo <acme@redhat.com>
Cc: Jiri Olsa <jolsa@redhat.com>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Stephane Eranian <eranian@google.com>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: Vince Weaver <vincent.weaver@maine.edu>
Cc: acme@kernel.org
Link: http://lkml.kernel.org/r/1518474035-21006-4-git-send-email-kan.liang@linux.intel.com


Signed-off-by: Ingo Molnar <mingo@kernel.org>

parent bcfbe5c4

arch/x86/events/intel/ds.c

+9 −0

Original line number	Diff line number	Diff line
		@@ -1306,6 +1306,15 @@ get_next_pebs_record_by_bit(void base, void top, int bit)
		return NULL;
		}

		void intel_pmu_auto_reload_read(struct perf_event *event)
		{
		WARN_ON(!(event->hw.flags & PERF_X86_EVENT_AUTO_RELOAD));

		perf_pmu_disable(event->pmu);
		intel_pmu_drain_pebs_buffer();
		perf_pmu_enable(event->pmu);
		}

		/*
		* Special variant of intel_pmu_save_and_restart() for auto-reload.
		*/

arch/x86/events/perf_event.h

+2 −0

Original line number	Diff line number	Diff line
		@@ -924,6 +924,8 @@ void intel_pmu_pebs_disable_all(void);

		void intel_pmu_pebs_sched_task(struct perf_event_context *ctx, bool sched_in);

		void intel_pmu_auto_reload_read(struct perf_event *event);

		void intel_ds_init(void);

		void intel_pmu_lbr_sched_task(struct perf_event_context *ctx, bool sched_in);