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perf: Convert perf_event to local_t

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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>
This commit is contained in:
Peter Zijlstra
2010-05-21 14:43:08 +02:00
committed by Ingo Molnar
parent a6e6dea68c
commit e78505958c
7 changed files with 72 additions and 71 deletions
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42
kernel/perf_event.c
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@@ -1148,9 +1148,9 @@ static void __perf_event_sync_stat(struct perf_event *event,
* 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 @@ static void perf_adjust_period(struct perf_event *event, u64 nsec, u64 count)
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 @@ static void perf_ctx_adjust_freq(struct perf_event_context *ctx)
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 void __perf_event_read(void *info)
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 unsigned int perf_poll(struct file *file, poll_table *wait)
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 @@ void perf_event_update_userpage(struct perf_event *event)
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 @@ static u64 perf_swevent_set_period(struct perf_event *event)
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 @@ static void perf_swevent_add(struct perf_event *event, u64 nr,
{
struct hw_perf_event *hwc = &event->hw;
atomic64_add(nr, &event->count);
local64_add(nr, &event->count);
if (!regs)
return;
@@ -4092,7 +4092,7 @@ static void perf_swevent_add(struct perf_event *event, u64 nr,
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 @@ static void cpu_clock_perf_event_update(struct perf_event *event)
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 @@ static int cpu_clock_perf_event_enable(struct perf_event *event)
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 @@ static void task_clock_perf_event_update(struct perf_event *event, u64 now)
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 @@ static int task_clock_perf_event_enable(struct perf_event *event)
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 @@ perf_event_alloc(struct perf_event_attr *attr,
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 @@ inherit_event(struct perf_event *parent_event,
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;