sched: add avg-overlap support to RT tasks
We have the notion of tracking process-coupling (a.k.a. buddy-wake) via
the p->se.last_wake / p->se.avg_overlap facilities, but it is only used
for cfs to cfs interactions. There is no reason why an rt to cfs
interaction cannot share in establishing a relationhip in a similar
manner.
Because PREEMPT_RT runs many kernel threads as FIFO priority, we often
times have heavy interaction between RT threads waking CFS applications.
This patch offers a substantial boost (50-60%+) in perfomance under those
circumstances.
Signed-off-by: Gregory Haskins <ghaskins@novell.com>
Cc: npiggin@suse.de
Cc: rostedt@goodmis.org
Acked-by: Peter Zijlstra <a.p.zijlstra@chello.nl>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
diff --git a/kernel/sched_fair.c b/kernel/sched_fair.c
index 2e43d4a..f2aa987 100644
--- a/kernel/sched_fair.c
+++ b/kernel/sched_fair.c
@@ -726,21 +726,6 @@
__enqueue_entity(cfs_rq, se);
}
-static void update_avg(u64 *avg, u64 sample)
-{
- s64 diff = sample - *avg;
- *avg += diff >> 3;
-}
-
-static void update_avg_stats(struct cfs_rq *cfs_rq, struct sched_entity *se)
-{
- if (!se->last_wakeup)
- return;
-
- update_avg(&se->avg_overlap, se->sum_exec_runtime - se->last_wakeup);
- se->last_wakeup = 0;
-}
-
static void
dequeue_entity(struct cfs_rq *cfs_rq, struct sched_entity *se, int sleep)
{
@@ -751,7 +736,6 @@
update_stats_dequeue(cfs_rq, se);
if (sleep) {
- update_avg_stats(cfs_rq, se);
#ifdef CONFIG_SCHEDSTATS
if (entity_is_task(se)) {
struct task_struct *tsk = task_of(se);
@@ -1196,9 +1180,9 @@
* a reasonable amount of time then attract this newly
* woken task:
*/
- if (sync && balanced && curr->sched_class == &fair_sched_class) {
+ if (sync && balanced) {
if (curr->se.avg_overlap < sysctl_sched_migration_cost &&
- p->se.avg_overlap < sysctl_sched_migration_cost)
+ p->se.avg_overlap < sysctl_sched_migration_cost)
return 1;
}
@@ -1359,7 +1343,6 @@
return;
}
- se->last_wakeup = se->sum_exec_runtime;
if (unlikely(se == pse))
return;