sched: keep total / count stats in addition to the max for
Right now, the linux kernel (with scheduler statistics enabled) keeps track
of the maximum time a process is waiting to be scheduled. While the maximum
is a very useful metric, tracking average and total is equally useful
(at least for latencytop) to figure out the accumulated effect of scheduler
delays. The accumulated effect is important to judge the performance impact
of scheduler tuning/behavior.
Signed-off-by: Arjan van de Ven <arjan@linux.intel.com>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
diff --git a/include/linux/sched.h b/include/linux/sched.h
index 734f6d8..df5b24e 100644
--- a/include/linux/sched.h
+++ b/include/linux/sched.h
@@ -895,6 +895,8 @@
#ifdef CONFIG_SCHEDSTATS
u64 wait_start;
u64 wait_max;
+ u64 wait_count;
+ u64 wait_sum;
u64 sleep_start;
u64 sleep_max;
diff --git a/kernel/sched_debug.c b/kernel/sched_debug.c
index 9e5de09..4b5e24c 100644
--- a/kernel/sched_debug.c
+++ b/kernel/sched_debug.c
@@ -300,6 +300,8 @@
PN(se.exec_max);
PN(se.slice_max);
PN(se.wait_max);
+ PN(se.wait_sum);
+ P(se.wait_count);
P(sched_info.bkl_count);
P(se.nr_migrations);
P(se.nr_migrations_cold);
@@ -367,6 +369,8 @@
{
#ifdef CONFIG_SCHEDSTATS
p->se.wait_max = 0;
+ p->se.wait_sum = 0;
+ p->se.wait_count = 0;
p->se.sleep_max = 0;
p->se.sum_sleep_runtime = 0;
p->se.block_max = 0;
diff --git a/kernel/sched_fair.c b/kernel/sched_fair.c
index 45ff4e9..72e25c7 100644
--- a/kernel/sched_fair.c
+++ b/kernel/sched_fair.c
@@ -385,6 +385,9 @@
{
schedstat_set(se->wait_max, max(se->wait_max,
rq_of(cfs_rq)->clock - se->wait_start));
+ schedstat_set(se->wait_count, se->wait_count + 1);
+ schedstat_set(se->wait_sum, se->wait_sum +
+ rq_of(cfs_rq)->clock - se->wait_start);
schedstat_set(se->wait_start, 0);
}
