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Commit 6d082592 authored by Arjan van de Ven's avatar Arjan van de Ven Committed by Ingo Molnar
Browse files

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: default avatarArjan van de Ven <arjan@linux.intel.com>
Signed-off-by: default avatarIngo Molnar <mingo@elte.hu>
parent 286100a6

include/linux/sched.h

+2 −0
Original line number Diff line number Diff line
@@ -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;

kernel/sched_debug.c

+4 −0
Original line number Diff line number Diff line
@@ -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;

kernel/sched_fair.c

+3 −0
Original line number Diff line number Diff line
@@ -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);

}