perf: Convert perf_event to local_t
Since now all modification to event->count (and ->prev_count
and ->period_left) are local to a cpu, change then to local64_t so we
avoid the LOCK'ed ops.
Signed-off-by: Peter Zijlstra <a.p.zijlstra@chello.nl>
LKML-Reference: <new-submission>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
diff --git a/kernel/perf_event.c b/kernel/perf_event.c
index a395fda..97c7301 100644
--- a/kernel/perf_event.c
+++ b/kernel/perf_event.c
@@ -1148,9 +1148,9 @@
* In order to keep per-task stats reliable we need to flip the event
* values when we flip the contexts.
*/
- value = atomic64_read(&next_event->count);
- value = atomic64_xchg(&event->count, value);
- atomic64_set(&next_event->count, value);
+ value = local64_read(&next_event->count);
+ value = local64_xchg(&event->count, value);
+ local64_set(&next_event->count, value);
swap(event->total_time_enabled, next_event->total_time_enabled);
swap(event->total_time_running, next_event->total_time_running);
@@ -1540,10 +1540,10 @@
hwc->sample_period = sample_period;
- if (atomic64_read(&hwc->period_left) > 8*sample_period) {
+ if (local64_read(&hwc->period_left) > 8*sample_period) {
perf_disable();
perf_event_stop(event);
- atomic64_set(&hwc->period_left, 0);
+ local64_set(&hwc->period_left, 0);
perf_event_start(event);
perf_enable();
}
@@ -1584,7 +1584,7 @@
perf_disable();
event->pmu->read(event);
- now = atomic64_read(&event->count);
+ now = local64_read(&event->count);
delta = now - hwc->freq_count_stamp;
hwc->freq_count_stamp = now;
@@ -1738,7 +1738,7 @@
static inline u64 perf_event_count(struct perf_event *event)
{
- return atomic64_read(&event->count) + atomic64_read(&event->child_count);
+ return local64_read(&event->count) + atomic64_read(&event->child_count);
}
static u64 perf_event_read(struct perf_event *event)
@@ -2141,7 +2141,7 @@
static void perf_event_reset(struct perf_event *event)
{
(void)perf_event_read(event);
- atomic64_set(&event->count, 0);
+ local64_set(&event->count, 0);
perf_event_update_userpage(event);
}
@@ -2359,7 +2359,7 @@
userpg->index = perf_event_index(event);
userpg->offset = perf_event_count(event);
if (event->state == PERF_EVENT_STATE_ACTIVE)
- userpg->offset -= atomic64_read(&event->hw.prev_count);
+ userpg->offset -= local64_read(&event->hw.prev_count);
userpg->time_enabled = event->total_time_enabled +
atomic64_read(&event->child_total_time_enabled);
@@ -4035,14 +4035,14 @@
hwc->last_period = hwc->sample_period;
again:
- old = val = atomic64_read(&hwc->period_left);
+ old = val = local64_read(&hwc->period_left);
if (val < 0)
return 0;
nr = div64_u64(period + val, period);
offset = nr * period;
val -= offset;
- if (atomic64_cmpxchg(&hwc->period_left, old, val) != old)
+ if (local64_cmpxchg(&hwc->period_left, old, val) != old)
goto again;
return nr;
@@ -4081,7 +4081,7 @@
{
struct hw_perf_event *hwc = &event->hw;
- atomic64_add(nr, &event->count);
+ local64_add(nr, &event->count);
if (!regs)
return;
@@ -4092,7 +4092,7 @@
if (nr == 1 && hwc->sample_period == 1 && !event->attr.freq)
return perf_swevent_overflow(event, 1, nmi, data, regs);
- if (atomic64_add_negative(nr, &hwc->period_left))
+ if (local64_add_negative(nr, &hwc->period_left))
return;
perf_swevent_overflow(event, 0, nmi, data, regs);
@@ -4383,8 +4383,8 @@
u64 now;
now = cpu_clock(cpu);
- prev = atomic64_xchg(&event->hw.prev_count, now);
- atomic64_add(now - prev, &event->count);
+ prev = local64_xchg(&event->hw.prev_count, now);
+ local64_add(now - prev, &event->count);
}
static int cpu_clock_perf_event_enable(struct perf_event *event)
@@ -4392,7 +4392,7 @@
struct hw_perf_event *hwc = &event->hw;
int cpu = raw_smp_processor_id();
- atomic64_set(&hwc->prev_count, cpu_clock(cpu));
+ local64_set(&hwc->prev_count, cpu_clock(cpu));
perf_swevent_start_hrtimer(event);
return 0;
@@ -4424,9 +4424,9 @@
u64 prev;
s64 delta;
- prev = atomic64_xchg(&event->hw.prev_count, now);
+ prev = local64_xchg(&event->hw.prev_count, now);
delta = now - prev;
- atomic64_add(delta, &event->count);
+ local64_add(delta, &event->count);
}
static int task_clock_perf_event_enable(struct perf_event *event)
@@ -4436,7 +4436,7 @@
now = event->ctx->time;
- atomic64_set(&hwc->prev_count, now);
+ local64_set(&hwc->prev_count, now);
perf_swevent_start_hrtimer(event);
@@ -4879,7 +4879,7 @@
hwc->sample_period = 1;
hwc->last_period = hwc->sample_period;
- atomic64_set(&hwc->period_left, hwc->sample_period);
+ local64_set(&hwc->period_left, hwc->sample_period);
/*
* we currently do not support PERF_FORMAT_GROUP on inherited events
@@ -5313,7 +5313,7 @@
hwc->sample_period = sample_period;
hwc->last_period = sample_period;
- atomic64_set(&hwc->period_left, sample_period);
+ local64_set(&hwc->period_left, sample_period);
}
child_event->overflow_handler = parent_event->overflow_handler;