From: Nikhil Rao <ncrao@google.com>
Date: Wed, 17 Nov 2010 19:42:04 +0000 (-0800)
Subject: sched: Fix idle balancing
X-Git-Url: http://git.cdn.openwrt.org/?a=commitdiff_plain;h=d5ad140bc1505a98c0f040937125bfcbb508078f;p=openwrt%2Fstaging%2Fblogic.git

sched: Fix idle balancing

An earlier commit reverts idle balancing throttling reset to fix a 30%
regression in volanomark throughput. We still need to reset idle_stamp
when we pull a task in newidle balance.

Reported-by: Alex Shi <alex.shi@intel.com>
Signed-off-by: Nikhil Rao <ncrao@google.com>
Signed-off-by: Peter Zijlstra <a.p.zijlstra@chello.nl>
LKML-Reference: <1290022924-3548-1-git-send-email-ncrao@google.com>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
---

diff --git a/kernel/sched_fair.c b/kernel/sched_fair.c
index ba0556dc7c06..00ebd7686676 100644
--- a/kernel/sched_fair.c
+++ b/kernel/sched_fair.c
@@ -3215,8 +3215,10 @@ static void idle_balance(int this_cpu, struct rq *this_rq)
 		interval = msecs_to_jiffies(sd->balance_interval);
 		if (time_after(next_balance, sd->last_balance + interval))
 			next_balance = sd->last_balance + interval;
-		if (pulled_task)
+		if (pulled_task) {
+			this_rq->idle_stamp = 0;
 			break;
+		}
 	}
 
 	raw_spin_lock(&this_rq->lock);