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perfcounters: add nr-of-faults counter

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Impact: add new feature, new sw counter

Add a counter that counts the number of pagefaults a task
is experiencing.

Signed-off-by: Ingo Molnar <mingo@elte.hu>
This commit is contained in:
Ingo Molnar 2008-12-14 14:44:31 +01:00
parent 6c594c21fc
commit e06c61a879
1 changed files with 51 additions and 0 deletions
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51
kernel/perf_counter.c
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@ -888,6 +888,54 @@ static const struct hw_perf_counter_ops perf_ops_task_clock = {
.hw_perf_counter_read = task_clock_perf_counter_read,
};
static u64 get_page_faults(void)
{
struct task_struct *curr = current;
return curr->maj_flt + curr->min_flt;
}
static void page_faults_perf_counter_update(struct perf_counter *counter)
{
u64 prev, now;
s64 delta;
prev = atomic64_read(&counter->hw.prev_count);
now = get_page_faults();
atomic64_set(&counter->hw.prev_count, now);
delta = now - prev;
if (WARN_ON_ONCE(delta < 0))
delta = 0;
atomic64_add(delta, &counter->count);
}
static void page_faults_perf_counter_read(struct perf_counter *counter)
{
page_faults_perf_counter_update(counter);
}
static void page_faults_perf_counter_enable(struct perf_counter *counter)
{
/*
* page-faults is a per-task value already,
* so we dont have to clear it on switch-in.
*/
}
static void page_faults_perf_counter_disable(struct perf_counter *counter)
{
page_faults_perf_counter_update(counter);
}
static const struct hw_perf_counter_ops perf_ops_page_faults = {
.hw_perf_counter_enable = page_faults_perf_counter_enable,
.hw_perf_counter_disable = page_faults_perf_counter_disable,
.hw_perf_counter_read = page_faults_perf_counter_read,
};
static u64 get_context_switches(void)
{
struct task_struct *curr = current;
@ -994,6 +1042,9 @@ sw_perf_counter_init(struct perf_counter *counter)
case PERF_COUNT_TASK_CLOCK:
hw_ops = &perf_ops_task_clock;
break;
case PERF_COUNT_PAGE_FAULTS:
hw_ops = &perf_ops_page_faults;
break;
case PERF_COUNT_CONTEXT_SWITCHES:
hw_ops = &perf_ops_context_switches;
break;