Commit-ID: 5bee2cc69d986e20808c93c46f7b6aef51edd827
Gitweb: https://git.kernel.org/tip/5bee2cc69d986e20808c93c46f7b6aef51edd827
Author: Kan Liang <kan.liang@xxxxxxxxxxxxxxx>
AuthorDate: Mon, 12 Feb 2018 14:20:33 -0800
Committer: Ingo Molnar <mingo@xxxxxxxxxx>
CommitDate: Fri, 9 Mar 2018 08:22:21 +0100
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@xxxxxxxxxxxxxxx>
Signed-off-by: Peter Zijlstra (Intel) <peterz@xxxxxxxxxxxxx>
Cc: Alexander Shishkin <alexander.shishkin@xxxxxxxxxxxxxxx>
Cc: Arnaldo Carvalho de Melo <acme@xxxxxxxxxx>
Cc: Jiri Olsa <jolsa@xxxxxxxxxx>
Cc: Linus Torvalds <torvalds@xxxxxxxxxxxxxxxxxxxx>
Cc: Peter Zijlstra <peterz@xxxxxxxxxxxxx>
Cc: Stephane Eranian <eranian@xxxxxxxxxx>
Cc: Thomas Gleixner <tglx@xxxxxxxxxxxxx>
Cc: Vince Weaver <vincent.weaver@xxxxxxxxx>
Cc: acme@xxxxxxxxxx
Link: http://lkml.kernel.org/r/1518474035-21006-4-git-send-email-kan.liang@xxxxxxxxxxxxxxx
Signed-off-by: Ingo Molnar <mingo@xxxxxxxxxx>
---
arch/x86/events/intel/ds.c | 9 +++++++++
arch/x86/events/perf_event.h | 2 ++
2 files changed, 11 insertions(+)
diff --git a/arch/x86/events/intel/ds.c b/arch/x86/events/intel/ds.c
index f39a4df3a7bd..73844025adaf 100644
--- a/arch/x86/events/intel/ds.c
+++ b/arch/x86/events/intel/ds.c
@@ -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.
*/
diff --git a/arch/x86/events/perf_event.h b/arch/x86/events/perf_event.h
index d445f0026989..91643472f385 100644
--- a/arch/x86/events/perf_event.h
+++ b/arch/x86/events/perf_event.h
@@ -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);
--
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