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Date: Mon, 23 Feb 2015 09:25:55 -0500
From: Kan Liang <kan.liang@...el.com>
To: a.p.zijlstra@...llo.nl, linux-kernel@...r.kernel.org
Cc: mingo@...nel.org, acme@...radead.org, eranian@...gle.com,
andi@...stfloor.org, Kan Liang <kan.liang@...el.com>
Subject: [PATCH V5 5/6] perf, x86: drain PEBS buffer during context switch
From: Yan, Zheng <zheng.z.yan@...el.com>
Flush the PEBS buffer during context switch if PEBS interrupt threshold
is larger than one. This allows perf to supply TID for sample outputs.
Signed-off-by: Yan, Zheng <zheng.z.yan@...el.com>
Signed-off-by: Kan Liang <kan.liang@...el.com>
---
arch/x86/kernel/cpu/perf_event.h | 3 +++
arch/x86/kernel/cpu/perf_event_intel.c | 11 +++++++++-
arch/x86/kernel/cpu/perf_event_intel_ds.c | 33 ++++++++++++++++++++++++++++--
arch/x86/kernel/cpu/perf_event_intel_lbr.c | 3 ---
4 files changed, 44 insertions(+), 6 deletions(-)
diff --git a/arch/x86/kernel/cpu/perf_event.h b/arch/x86/kernel/cpu/perf_event.h
index bc4ae3b..b4f6431 100644
--- a/arch/x86/kernel/cpu/perf_event.h
+++ b/arch/x86/kernel/cpu/perf_event.h
@@ -151,6 +151,7 @@ struct cpu_hw_events {
*/
struct debug_store *ds;
u64 pebs_enabled;
+ bool pebs_sched_cb_enabled;
/*
* Intel LBR bits
@@ -739,6 +740,8 @@ void intel_pmu_pebs_enable_all(void);
void intel_pmu_pebs_disable_all(void);
+void intel_pmu_pebs_sched_task(struct perf_event_context *ctx, bool sched_in);
+
void intel_ds_init(void);
void intel_pmu_lbr_sched_task(struct perf_event_context *ctx, bool sched_in);
diff --git a/arch/x86/kernel/cpu/perf_event_intel.c b/arch/x86/kernel/cpu/perf_event_intel.c
index 9f1dd18..bdb2ffd 100644
--- a/arch/x86/kernel/cpu/perf_event_intel.c
+++ b/arch/x86/kernel/cpu/perf_event_intel.c
@@ -2030,6 +2030,15 @@ static void intel_pmu_cpu_dying(int cpu)
fini_debug_store_on_cpu(cpu);
}
+static void intel_pmu_sched_task(struct perf_event_context *ctx,
+ bool sched_in)
+{
+ if (x86_pmu.pebs_active)
+ intel_pmu_pebs_sched_task(ctx, sched_in);
+ if (x86_pmu.lbr_nr)
+ intel_pmu_lbr_sched_task(ctx, sched_in);
+}
+
PMU_FORMAT_ATTR(offcore_rsp, "config1:0-63");
PMU_FORMAT_ATTR(ldlat, "config1:0-15");
@@ -2081,7 +2090,7 @@ static __initconst const struct x86_pmu intel_pmu = {
.cpu_starting = intel_pmu_cpu_starting,
.cpu_dying = intel_pmu_cpu_dying,
.guest_get_msrs = intel_guest_get_msrs,
- .sched_task = intel_pmu_lbr_sched_task,
+ .sched_task = intel_pmu_sched_task,
};
static __init void intel_clovertown_quirk(void)
diff --git a/arch/x86/kernel/cpu/perf_event_intel_ds.c b/arch/x86/kernel/cpu/perf_event_intel_ds.c
index cf74a52..b8d0451 100644
--- a/arch/x86/kernel/cpu/perf_event_intel_ds.c
+++ b/arch/x86/kernel/cpu/perf_event_intel_ds.c
@@ -664,6 +664,19 @@ struct event_constraint *intel_pebs_constraints(struct perf_event *event)
return &emptyconstraint;
}
+static inline void intel_pmu_drain_pebs_buffer(void)
+{
+ struct pt_regs regs;
+
+ x86_pmu.drain_pebs(®s);
+}
+
+void intel_pmu_pebs_sched_task(struct perf_event_context *ctx, bool sched_in)
+{
+ if (!sched_in)
+ intel_pmu_drain_pebs_buffer();
+}
+
/*
* Flags PEBS can handle without an PMI.
*
@@ -704,13 +717,20 @@ void intel_pmu_pebs_enable(struct perf_event *event)
* When the event is constrained enough we can use a larger
* threshold and run the event with less frequent PMI.
*/
- if (0 && /* disable this temporarily */
- (hwc->flags & PERF_X86_EVENT_AUTO_RELOAD) &&
+ if ((hwc->flags & PERF_X86_EVENT_AUTO_RELOAD) &&
!(event->attr.sample_type & ~PEBS_FREERUNNING_FLAGS)) {
threshold = ds->pebs_absolute_maximum -
x86_pmu.max_pebs_events * x86_pmu.pebs_record_size;
+ if (first_pebs) {
+ perf_sched_cb_inc(event->ctx->pmu);
+ cpuc->pebs_sched_cb_enabled = true;
+ }
} else {
threshold = ds->pebs_buffer_base + x86_pmu.pebs_record_size;
+ if (cpuc->pebs_sched_cb_enabled) {
+ perf_sched_cb_dec(event->ctx->pmu);
+ cpuc->pebs_sched_cb_enabled = false;
+ }
}
if (first_pebs || ds->pebs_interrupt_threshold > threshold)
ds->pebs_interrupt_threshold = threshold;
@@ -726,8 +746,17 @@ void intel_pmu_pebs_disable(struct perf_event *event)
{
struct cpu_hw_events *cpuc = this_cpu_ptr(&cpu_hw_events);
struct hw_perf_event *hwc = &event->hw;
+ struct debug_store *ds = cpuc->ds;
+
+ if (ds->pebs_interrupt_threshold >
+ ds->pebs_buffer_base + x86_pmu.pebs_record_size)
+ intel_pmu_drain_pebs_buffer();
cpuc->pebs_enabled &= ~(1ULL << hwc->idx);
+ if (cpuc->pebs_sched_cb_enabled && !pebs_is_enabled(cpuc)) {
+ perf_sched_cb_dec(event->ctx->pmu);
+ cpuc->pebs_sched_cb_enabled = false;
+ }
if (event->hw.constraint->flags & PERF_X86_EVENT_PEBS_LDLAT)
cpuc->pebs_enabled &= ~(1ULL << (hwc->idx + 32));
diff --git a/arch/x86/kernel/cpu/perf_event_intel_lbr.c b/arch/x86/kernel/cpu/perf_event_intel_lbr.c
index 0473874..1edd3b9 100644
--- a/arch/x86/kernel/cpu/perf_event_intel_lbr.c
+++ b/arch/x86/kernel/cpu/perf_event_intel_lbr.c
@@ -256,9 +256,6 @@ void intel_pmu_lbr_sched_task(struct perf_event_context *ctx, bool sched_in)
struct cpu_hw_events *cpuc = this_cpu_ptr(&cpu_hw_events);
struct x86_perf_task_context *task_ctx;
- if (!x86_pmu.lbr_nr)
- return;
-
/*
* If LBR callstack feature is enabled and the stack was saved when
* the task was scheduled out, restore the stack. Otherwise flush
--
1.8.3.2
--
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