[PATCH 3/8] sched: weaken sync hint

[Peter Zijlstra <a.p.zijlstra@chello.nl>]

[-- Attachment #1: mike-weaken-sync.patch --]
[-- Type: text/plain, Size: 1116 bytes --]

From: Mike Galbraith <efault@gmx.de>

Mysql+oltp and pgsql+oltp peaks are still shifted right. The below puts
the peaks back to 1 client/server pair per core.

Use the avg_overlap information to weaken the sync hint.

Signed-off-by: Mike Galbraith <efault@gmx.de>
Signed-off-by: Peter Zijlstra <a.p.zijlstra@chello.nl>
---
 kernel/sched_fair.c |    7 +++----
 1 file changed, 3 insertions(+), 4 deletions(-)

Index: linux-2.6/kernel/sched_fair.c
===================================================================
--- linux-2.6.orig/kernel/sched_fair.c
+++ linux-2.6/kernel/sched_fair.c
@@ -1228,10 +1228,9 @@ wake_affine(struct sched_domain *this_sd
 	if (!(this_sd->flags & SD_WAKE_AFFINE) || !sched_feat(AFFINE_WAKEUPS))
 		return 0;
 
-	if (!sync && sched_feat(SYNC_WAKEUPS) &&
-	    curr->se.avg_overlap < sysctl_sched_migration_cost &&
-	    p->se.avg_overlap < sysctl_sched_migration_cost)
-		sync = 1;
+	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)

--