From: Nikhil Rao <ncrao@google.com>
Date: Thu, 10 Feb 2011 09:23:29 +0000 (+0100)
Subject: sched: Fix idle balancing
X-Git-Tag: firefly_0821_release~10186^2~459
X-Git-Url: http://demsky.eecs.uci.edu/git/?a=commitdiff_plain;h=354f5613d804571fa88ecff8eec02d5ba57d8b07;p=firefly-linux-kernel-4.4.55.git

sched: Fix idle balancing

Commit: d5ad140bc1505a98c0f040937125bfcbb508078f upstream

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>
Signed-off-by: Mike Galbraith <efault@gmx.de>
Acked-by: Peter Zijlstra <a.p.zijlstra@chello.nl>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>
---

diff --git a/kernel/sched.c b/kernel/sched.c
index ffd4f574008f..f4e1f4ebf4fa 100644
--- a/kernel/sched.c
+++ b/kernel/sched.c
@@ -4692,8 +4692,10 @@ 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;
+		}
 	}
 	if (pulled_task || time_after(jiffies, this_rq->next_balance)) {
 		/*