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authorPeter Zijlstra <a.p.zijlstra@chello.nl>2009-01-26 17:56:17 +0100
committerIngo Molnar <mingo@elte.hu>2009-02-01 10:49:06 +0100
commitd942fb6c7d391baba3dddb566eb735fbf3df8528 (patch)
tree0340b810c79f873b7aea34298aa22e2ebf740df3
parentf90d4118bacef87894621a3e8aba853fa0c89abc (diff)
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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: Pawel Dziekonski <dzieko@gmail.com> Signed-off-by: Peter Zijlstra <a.p.zijlstra@chello.nl> Signed-off-by: Ingo Molnar <mingo@elte.hu>
-rw-r--r--kernel/sched.c4
-rw-r--r--kernel/sched_fair.c11
2 files changed, 6 insertions, 9 deletions
diff --git a/kernel/sched.c b/kernel/sched.c
index 52bbf1c842a8..770b1f9ebe14 100644
--- a/kernel/sched.c
+++ b/kernel/sched.c
@@ -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;
+
#ifdef CONFIG_SMP
if (sched_feat(LB_WAKEUP_UPDATE)) {
struct sched_domain *sd;
diff --git a/kernel/sched_fair.c b/kernel/sched_fair.c
index 5cc1c162044f..fdc417504681 100644
--- a/kernel/sched_fair.c
+++ b/kernel/sched_fair.c
@@ -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))
return;
- 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) {
resched_task(curr);
return;
}