perf_counter: rework context time
Since perf_counter_context is switched along with tasks, we can maintain the context time without using the task runtime clock. Signed-off-by: Peter Zijlstra <a.p.zijlstra@chello.nl> Cc: Paul Mackerras <paulus@samba.org> Cc: Corey Ashford <cjashfor@linux.vnet.ibm.com> LKML-Reference: <20090406094518.353552838@chello.nl> Signed-off-by: Ingo Molnar <mingo@elte.hu>
This commit is contained in:
Peter Zijlstra
Ingo Molnar
Родитель
4c9e25428f
Коммит
4af4998b8a
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@ -477,14 +477,10 @@ struct perf_counter_context {
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struct task_struct *task;
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/*
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* time_now is the current time in nanoseconds since an arbitrary
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* point in the past. For per-task counters, this is based on the
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* task clock, and for per-cpu counters it is based on the cpu clock.
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* time_lost is an offset from the task/cpu clock, used to make it
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* appear that time only passes while the context is scheduled in.
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* Context clock, runs when context enabled.
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*/
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u64 time_now;
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u64 time_lost;
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u64 time;
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u64 timestamp;
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#endif
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};
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@ -117,7 +117,7 @@ counter_sched_out(struct perf_counter *counter,
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return;
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counter->state = PERF_COUNTER_STATE_INACTIVE;
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counter->tstamp_stopped = ctx->time_now;
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counter->tstamp_stopped = ctx->time;
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counter->hw_ops->disable(counter);
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counter->oncpu = -1;
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@ -253,27 +253,20 @@ retry:
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spin_unlock_irq(&ctx->lock);
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}
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/*
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* Get the current time for this context.
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* If this is a task context, we use the task's task clock,
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* or for a per-cpu context, we use the cpu clock.
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*/
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static u64 get_context_time(struct perf_counter_context *ctx, int update)
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static inline u64 perf_clock(void)
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{
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struct task_struct *curr = ctx->task;
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if (!curr)
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return cpu_clock(smp_processor_id());
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return __task_delta_exec(curr, update) + curr->se.sum_exec_runtime;
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return cpu_clock(smp_processor_id());
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}
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/*
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* Update the record of the current time in a context.
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*/
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static void update_context_time(struct perf_counter_context *ctx, int update)
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static void update_context_time(struct perf_counter_context *ctx)
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{
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ctx->time_now = get_context_time(ctx, update) - ctx->time_lost;
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u64 now = perf_clock();
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ctx->time += now - ctx->timestamp;
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ctx->timestamp = now;
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}
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/*
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@ -284,15 +277,17 @@ static void update_counter_times(struct perf_counter *counter)
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struct perf_counter_context *ctx = counter->ctx;
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u64 run_end;
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if (counter->state >= PERF_COUNTER_STATE_INACTIVE) {
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counter->total_time_enabled = ctx->time_now -
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counter->tstamp_enabled;
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if (counter->state == PERF_COUNTER_STATE_INACTIVE)
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run_end = counter->tstamp_stopped;
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else
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run_end = ctx->time_now;
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counter->total_time_running = run_end - counter->tstamp_running;
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}
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if (counter->state < PERF_COUNTER_STATE_INACTIVE)
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return;
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counter->total_time_enabled = ctx->time - counter->tstamp_enabled;
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if (counter->state == PERF_COUNTER_STATE_INACTIVE)
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run_end = counter->tstamp_stopped;
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else
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run_end = ctx->time;
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counter->total_time_running = run_end - counter->tstamp_running;
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}
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/*
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@ -332,7 +327,7 @@ static void __perf_counter_disable(void *info)
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* If it is in error state, leave it in error state.
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*/
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if (counter->state >= PERF_COUNTER_STATE_INACTIVE) {
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update_context_time(ctx, 1);
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update_context_time(ctx);
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update_counter_times(counter);
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if (counter == counter->group_leader)
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group_sched_out(counter, cpuctx, ctx);
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@ -426,7 +421,7 @@ counter_sched_in(struct perf_counter *counter,
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return -EAGAIN;
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}
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counter->tstamp_running += ctx->time_now - counter->tstamp_stopped;
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counter->tstamp_running += ctx->time - counter->tstamp_stopped;
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if (!is_software_counter(counter))
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cpuctx->active_oncpu++;
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@ -493,9 +488,9 @@ static void add_counter_to_ctx(struct perf_counter *counter,
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list_add_counter(counter, ctx);
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ctx->nr_counters++;
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counter->prev_state = PERF_COUNTER_STATE_OFF;
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counter->tstamp_enabled = ctx->time_now;
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counter->tstamp_running = ctx->time_now;
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counter->tstamp_stopped = ctx->time_now;
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counter->tstamp_enabled = ctx->time;
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counter->tstamp_running = ctx->time;
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counter->tstamp_stopped = ctx->time;
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}
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/*
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@ -522,7 +517,7 @@ static void __perf_install_in_context(void *info)
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curr_rq_lock_irq_save(&flags);
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spin_lock(&ctx->lock);
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update_context_time(ctx, 1);
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update_context_time(ctx);
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/*
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* Protect the list operation against NMI by disabling the
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@ -648,13 +643,13 @@ static void __perf_counter_enable(void *info)
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curr_rq_lock_irq_save(&flags);
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spin_lock(&ctx->lock);
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update_context_time(ctx, 1);
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update_context_time(ctx);
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counter->prev_state = counter->state;
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if (counter->state >= PERF_COUNTER_STATE_INACTIVE)
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goto unlock;
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counter->state = PERF_COUNTER_STATE_INACTIVE;
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counter->tstamp_enabled = ctx->time_now - counter->total_time_enabled;
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counter->tstamp_enabled = ctx->time - counter->total_time_enabled;
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/*
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* If the counter is in a group and isn't the group leader,
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@ -737,8 +732,8 @@ static void perf_counter_enable(struct perf_counter *counter)
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*/
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if (counter->state == PERF_COUNTER_STATE_OFF) {
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counter->state = PERF_COUNTER_STATE_INACTIVE;
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counter->tstamp_enabled = ctx->time_now -
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counter->total_time_enabled;
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counter->tstamp_enabled =
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ctx->time - counter->total_time_enabled;
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}
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out:
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spin_unlock_irq(&ctx->lock);
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@ -778,7 +773,7 @@ void __perf_counter_sched_out(struct perf_counter_context *ctx,
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ctx->is_active = 0;
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if (likely(!ctx->nr_counters))
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goto out;
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update_context_time(ctx, 0);
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update_context_time(ctx);
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flags = hw_perf_save_disable();
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if (ctx->nr_active) {
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@ -883,12 +878,7 @@ __perf_counter_sched_in(struct perf_counter_context *ctx,
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if (likely(!ctx->nr_counters))
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goto out;
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/*
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* Add any time since the last sched_out to the lost time
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* so it doesn't get included in the total_time_enabled and
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* total_time_running measures for counters in the context.
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*/
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ctx->time_lost = get_context_time(ctx, 0) - ctx->time_now;
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ctx->timestamp = perf_clock();
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flags = hw_perf_save_disable();
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@ -1043,8 +1033,8 @@ int perf_counter_task_enable(void)
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if (counter->state > PERF_COUNTER_STATE_OFF)
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continue;
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counter->state = PERF_COUNTER_STATE_INACTIVE;
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counter->tstamp_enabled = ctx->time_now -
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counter->total_time_enabled;
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counter->tstamp_enabled =
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ctx->time - counter->total_time_enabled;
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counter->hw_event.disabled = 0;
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}
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hw_perf_restore(perf_flags);
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@ -1113,7 +1103,7 @@ static void __read(void *info)
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curr_rq_lock_irq_save(&flags);
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if (ctx->is_active)
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update_context_time(ctx, 1);
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update_context_time(ctx);
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counter->hw_ops->read(counter);
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update_counter_times(counter);
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curr_rq_unlock_irq_restore(&flags);
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