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sched: keep total / count stats in addition to the max for

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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>
This commit is contained in:
Arjan van de Ven 2008-01-25 21:08:35 +01:00 committed by Ingo Molnar
parent 286100a6cf
commit 6d082592b6
3 changed files with 9 additions and 0 deletions
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2
include/linux/sched.h
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@ -895,6 +895,8 @@ struct sched_entity {
#ifdef CONFIG_SCHEDSTATS
u64 wait_start;
u64 wait_max;
u64 wait_count;
u64 wait_sum;
u64 sleep_start;
u64 sleep_max;

4
kernel/sched_debug.c
View File

@ -300,6 +300,8 @@ void proc_sched_show_task(struct task_struct *p, struct seq_file *m)
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 @@ void proc_sched_set_task(struct task_struct *p)
{
#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;

3
kernel/sched_fair.c
View File

@ -385,6 +385,9 @@ update_stats_wait_end(struct cfs_rq *cfs_rq, struct sched_entity *se)
{
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);
}