Commit d942fb6c authored by Peter Zijlstra's avatar Peter Zijlstra Committed by Ingo Molnar
Browse files

sched: fix sync wakeups

Pawel Dziekonski reported that the openssl benchmark and his
quantum chemistry application both show slowdowns due to the
scheduler under-parallelizing execution.

The reason are pipe wakeups still doing 'sync' wakeups which
overrides the normal buddy wakeup logic - even if waker and
wakee are loosely coupled.

Fix an inversion of logic in the buddy wakeup code.
Reported-by: default avatarPawel Dziekonski <>
Signed-off-by: default avatarPeter Zijlstra <>
Signed-off-by: default avatarIngo Molnar <>
parent f90d4118
......@@ -2266,6 +2266,10 @@ static int try_to_wake_up(struct task_struct *p, unsigned int state, int sync)
if (!sched_feat(SYNC_WAKEUPS))
sync = 0;
if (!sync && (current->se.avg_overlap < sysctl_sched_migration_cost &&
p->se.avg_overlap < sysctl_sched_migration_cost))
sync = 1;
if (sched_feat(LB_WAKEUP_UPDATE)) {
struct sched_domain *sd;
......@@ -1179,20 +1179,15 @@ wake_affine(struct sched_domain *this_sd, struct rq *this_rq,
int idx, unsigned long load, unsigned long this_load,
unsigned int imbalance)
struct task_struct *curr = this_rq->curr;
struct task_group *tg;
unsigned long tl = this_load;
unsigned long tl_per_task;
struct task_group *tg;
unsigned long weight;
int balanced;
if (!(this_sd->flags & SD_WAKE_AFFINE) || !sched_feat(AFFINE_WAKEUPS))
return 0;
if (sync && (curr->se.avg_overlap > sysctl_sched_migration_cost ||
p->se.avg_overlap > sysctl_sched_migration_cost))
sync = 0;
* If sync wakeup then subtract the (maximum possible)
* effect of the currently running task from the load
......@@ -1419,9 +1414,7 @@ static void check_preempt_wakeup(struct rq *rq, struct task_struct *p, int sync)
if (!sched_feat(WAKEUP_PREEMPT))
if (sched_feat(WAKEUP_OVERLAP) && (sync ||
(se->avg_overlap < sysctl_sched_migration_cost &&
pse->avg_overlap < sysctl_sched_migration_cost))) {
if (sched_feat(WAKEUP_OVERLAP) && sync) {
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