Commit 6c594c21 authored by Ingo Molnar's avatar Ingo Molnar

perfcounters: add task migrations counter

Impact: add new feature, new sw counter

Add a counter that counts the number of cross-CPU migrations a
task is suffering.
Signed-off-by: default avatarIngo Molnar <mingo@elte.hu>
parent 5d6a27d8
No related merge requests found
...@@ -42,6 +42,8 @@ enum hw_event_types { ...@@ -42,6 +42,8 @@ enum hw_event_types {
PERF_COUNT_BRANCH_INSTRUCTIONS = 4, PERF_COUNT_BRANCH_INSTRUCTIONS = 4,
PERF_COUNT_BRANCH_MISSES = 5, PERF_COUNT_BRANCH_MISSES = 5,
PERF_HW_EVENTS_MAX = 6,
/* /*
* Special "software" counters provided by the kernel, even if * Special "software" counters provided by the kernel, even if
* the hardware does not support performance counters. These * the hardware does not support performance counters. These
...@@ -50,11 +52,11 @@ enum hw_event_types { ...@@ -50,11 +52,11 @@ enum hw_event_types {
*/ */
PERF_COUNT_CPU_CLOCK = -1, PERF_COUNT_CPU_CLOCK = -1,
PERF_COUNT_TASK_CLOCK = -2, PERF_COUNT_TASK_CLOCK = -2,
/*
* Future software events:
*/
PERF_COUNT_PAGE_FAULTS = -3, PERF_COUNT_PAGE_FAULTS = -3,
PERF_COUNT_CONTEXT_SWITCHES = -4, PERF_COUNT_CONTEXT_SWITCHES = -4,
PERF_COUNT_CPU_MIGRATIONS = -5,
PERF_SW_EVENTS_MIN = -6,
}; };
/* /*
......
...@@ -1014,6 +1014,8 @@ struct sched_entity { ...@@ -1014,6 +1014,8 @@ struct sched_entity {
u64 last_wakeup; u64 last_wakeup;
u64 avg_overlap; u64 avg_overlap;
u64 nr_migrations;
#ifdef CONFIG_SCHEDSTATS #ifdef CONFIG_SCHEDSTATS
u64 wait_start; u64 wait_start;
u64 wait_max; u64 wait_max;
...@@ -1029,7 +1031,6 @@ struct sched_entity { ...@@ -1029,7 +1031,6 @@ struct sched_entity {
u64 exec_max; u64 exec_max;
u64 slice_max; u64 slice_max;
u64 nr_migrations;
u64 nr_migrations_cold; u64 nr_migrations_cold;
u64 nr_failed_migrations_affine; u64 nr_failed_migrations_affine;
u64 nr_failed_migrations_running; u64 nr_failed_migrations_running;
......
...@@ -936,6 +936,52 @@ static const struct hw_perf_counter_ops perf_ops_context_switches = { ...@@ -936,6 +936,52 @@ static const struct hw_perf_counter_ops perf_ops_context_switches = {
.hw_perf_counter_read = context_switches_perf_counter_read, .hw_perf_counter_read = context_switches_perf_counter_read,
}; };
static inline u64 get_cpu_migrations(void)
{
return current->se.nr_migrations;
}
static void cpu_migrations_perf_counter_update(struct perf_counter *counter)
{
u64 prev, now;
s64 delta;
prev = atomic64_read(&counter->hw.prev_count);
now = get_cpu_migrations();
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 cpu_migrations_perf_counter_read(struct perf_counter *counter)
{
cpu_migrations_perf_counter_update(counter);
}
static void cpu_migrations_perf_counter_enable(struct perf_counter *counter)
{
/*
* se.nr_migrations is a per-task value already,
* so we dont have to clear it on switch-in.
*/
}
static void cpu_migrations_perf_counter_disable(struct perf_counter *counter)
{
cpu_migrations_perf_counter_update(counter);
}
static const struct hw_perf_counter_ops perf_ops_cpu_migrations = {
.hw_perf_counter_enable = cpu_migrations_perf_counter_enable,
.hw_perf_counter_disable = cpu_migrations_perf_counter_disable,
.hw_perf_counter_read = cpu_migrations_perf_counter_read,
};
static const struct hw_perf_counter_ops * static const struct hw_perf_counter_ops *
sw_perf_counter_init(struct perf_counter *counter) sw_perf_counter_init(struct perf_counter *counter)
{ {
...@@ -951,6 +997,9 @@ sw_perf_counter_init(struct perf_counter *counter) ...@@ -951,6 +997,9 @@ sw_perf_counter_init(struct perf_counter *counter)
case PERF_COUNT_CONTEXT_SWITCHES: case PERF_COUNT_CONTEXT_SWITCHES:
hw_ops = &perf_ops_context_switches; hw_ops = &perf_ops_context_switches;
break; break;
case PERF_COUNT_CPU_MIGRATIONS:
hw_ops = &perf_ops_cpu_migrations;
break;
default: default:
break; break;
} }
......
...@@ -1852,12 +1852,14 @@ void set_task_cpu(struct task_struct *p, unsigned int new_cpu) ...@@ -1852,12 +1852,14 @@ void set_task_cpu(struct task_struct *p, unsigned int new_cpu)
p->se.sleep_start -= clock_offset; p->se.sleep_start -= clock_offset;
if (p->se.block_start) if (p->se.block_start)
p->se.block_start -= clock_offset; p->se.block_start -= clock_offset;
#endif
if (old_cpu != new_cpu) { if (old_cpu != new_cpu) {
schedstat_inc(p, se.nr_migrations); p->se.nr_migrations++;
#ifdef CONFIG_SCHEDSTATS
if (task_hot(p, old_rq->clock, NULL)) if (task_hot(p, old_rq->clock, NULL))
schedstat_inc(p, se.nr_forced2_migrations); schedstat_inc(p, se.nr_forced2_migrations);
}
#endif #endif
}
p->se.vruntime -= old_cfsrq->min_vruntime - p->se.vruntime -= old_cfsrq->min_vruntime -
new_cfsrq->min_vruntime; new_cfsrq->min_vruntime;
...@@ -2375,6 +2377,7 @@ static void __sched_fork(struct task_struct *p) ...@@ -2375,6 +2377,7 @@ static void __sched_fork(struct task_struct *p)
p->se.exec_start = 0; p->se.exec_start = 0;
p->se.sum_exec_runtime = 0; p->se.sum_exec_runtime = 0;
p->se.prev_sum_exec_runtime = 0; p->se.prev_sum_exec_runtime = 0;
p->se.nr_migrations = 0;
p->se.last_wakeup = 0; p->se.last_wakeup = 0;
p->se.avg_overlap = 0; p->se.avg_overlap = 0;
......
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