[PATCH 1/3] sched: symmetric sync vs avg_overlap

From: Peter Zijlstra
Date: Wed Jan 28 2009 - 08:56:41 EST


Reinstate the weakening of the sync hint if set. This yields a more
symmetric usage of avg_overlap.

Signed-off-by: Peter Zijlstra <a.p.zijlstra@xxxxxxxxx>
---
kernel/sched.c | 12 +++++++++---
1 file changed, 9 insertions(+), 3 deletions(-)

Index: linux-2.6/kernel/sched.c
===================================================================
--- linux-2.6.orig/kernel/sched.c
+++ linux-2.6/kernel/sched.c
@@ -2360,9 +2360,15 @@ static int try_to_wake_up(struct task_st
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 (!sync) {
+ if (current->se.avg_overlap < sysctl_sched_migration_cost &&
+ p->se.avg_overlap < sysctl_sched_migration_cost)
+ sync = 1;
+ } else {
+ if (current->se.avg_overlap >= sysctl_sched_migration_cost ||
+ p->se.avg_overlap >= sysctl_sched_migration_cost)
+ sync = 0;
+ }

#ifdef CONFIG_SMP
if (sched_feat(LB_WAKEUP_UPDATE)) {

--

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