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Subject[PATCH 13/15] perf_counter: rework the task clock software counter
Rework the task clock software counter to use the context time instead
of the task runtime clock, this removes the last such user.

Signed-off-by: Peter Zijlstra <a.p.zijlstra@chello.nl>
---
kernel/perf_counter.c | 42 ++++++++++++------------------------------
1 file changed, 12 insertions(+), 30 deletions(-)
Index: linux-2.6/kernel/perf_counter.c
===================================================================
--- linux-2.6.orig/kernel/perf_counter.c
+++ linux-2.6/kernel/perf_counter.c
@@ -974,9 +974,6 @@ int perf_counter_task_disable(void)
curr_rq_lock_irq_save(&flags);
cpu = smp_processor_id();

- /* force the update of the task clock: */
- __task_delta_exec(curr, 1);
-
perf_counter_task_sched_out(curr, cpu);

spin_lock(&ctx->lock);
@@ -1017,9 +1014,6 @@ int perf_counter_task_enable(void)
curr_rq_lock_irq_save(&flags);
cpu = smp_processor_id();

- /* force the update of the task clock: */
- __task_delta_exec(curr, 1);
-
perf_counter_task_sched_out(curr, cpu);

spin_lock(&ctx->lock);
@@ -2347,38 +2341,28 @@ static const struct hw_perf_counter_ops
* Software counter: task time clock
*/

-/*
- * Called from within the scheduler:
- */
-static u64 task_clock_perf_counter_val(struct perf_counter *counter, int update)
-{
- struct task_struct *curr = counter->task;
- u64 delta;
-
- delta = __task_delta_exec(curr, update);
-
- return curr->se.sum_exec_runtime + delta;
-}
-
-static void task_clock_perf_counter_update(struct perf_counter *counter, u64 now)
+static void task_clock_perf_counter_update(struct perf_counter *counter)
{
- u64 prev;
+ u64 prev, now;
s64 delta;

- prev = atomic64_read(&counter->hw.prev_count);
-
- atomic64_set(&counter->hw.prev_count, now);
+ update_context_time(counter->ctx);
+ now = counter->ctx->time;

+ prev = atomic64_xchg(&counter->hw.prev_count, now);
delta = now - prev;
-
atomic64_add(delta, &counter->count);
}

static int task_clock_perf_counter_enable(struct perf_counter *counter)
{
struct hw_perf_counter *hwc = &counter->hw;
+ u64 now;
+
+ update_context_time(counter->ctx);
+ now = counter->ctx->time;

- atomic64_set(&hwc->prev_count, task_clock_perf_counter_val(counter, 0));
+ atomic64_set(&hwc->prev_count, now);
hrtimer_init(&hwc->hrtimer, CLOCK_MONOTONIC, HRTIMER_MODE_REL);
hwc->hrtimer.function = perf_swcounter_hrtimer;
if (hwc->irq_period) {
@@ -2393,14 +2377,12 @@ static int task_clock_perf_counter_enabl
static void task_clock_perf_counter_disable(struct perf_counter *counter)
{
hrtimer_cancel(&counter->hw.hrtimer);
- task_clock_perf_counter_update(counter,
- task_clock_perf_counter_val(counter, 0));
+ task_clock_perf_counter_update(counter);
}

static void task_clock_perf_counter_read(struct perf_counter *counter)
{
- task_clock_perf_counter_update(counter,
- task_clock_perf_counter_val(counter, 1));
+ task_clock_perf_counter_update(counter);
}

static const struct hw_perf_counter_ops perf_ops_task_clock = {
--



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