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From: Diwakar Tundlam <dtundlam@nvidia.com>
To: Ingo Molnar <mingo@elte.hu>,
	"'Peter Zijlstra'" <peterz@infradead.org>,
	"'Jens Axboe'" <jaxboe@fusionio.com>,
	"'Randy Dunlap'" <randy.dunlap@oracle.com>
Cc: Peter De Schrijver <pdeschrijver@nvidia.com>,
	"linux-kernel@vger.kernel.org" <linux-kernel@vger.kernel.org>,
	"'Linus Torvalds'" <torvalds@linux-foundation.org>
Subject: [PATCH] scheduler: domain: correctly initialize 'next_balance' in 'nohz' idle balancer
Date: Wed, 7 Mar 2012 14:44:26 -0800	[thread overview]
Message-ID: <1DD7BFEDD3147247B1355BEFEFE4665237994F30EF@HQMAIL04.nvidia.com> (raw)
In-Reply-To: <1328040137.2446.242.camel@twins>

scheduler: domain: init next_balance in nohz_idle_balancer with jiffies

The 'next_balance' field of 'nohz' idle balancer must be initialized
to jiffies. Since jiffies is initialized to negative 300 seconds the
'nohz' idle balancer does not run for the first 300s (5mins) after
bootup. If no new processes are spawed or no idle cycles happen, the
load on the cpus will remain unbalanced for that duration.

Signed-off-by: Diwakar Tundlam <dtundlam@nvidia.com>
---
 1 files changed, 1 insertions(+), 0 deletions(-)

diff -up sched/fair.c{.orig,}
--- sched/fair.c.orig	2012-03-07 08:33:03.000000000 -0800
+++ sched/fair.c	2012-03-07 13:50:30.787265795 -0800
@@ -5614,6 +5614,7 @@ __init void init_sched_fair_class(void)
 	open_softirq(SCHED_SOFTIRQ, run_rebalance_domains);
 
 #ifdef CONFIG_NO_HZ
+	nohz.next_balance = jiffies;
 	zalloc_cpumask_var(&nohz.idle_cpus_mask, GFP_NOWAIT);
 	cpu_notifier(sched_ilb_notifier, 0);
 #endif

  reply	other threads:[~2012-03-07 22:44 UTC|newest]

Thread overview: 12+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2012-01-30 12:44 [PATCH] scheduler: domain: init next_balance in nohz_idle_balancer with jiffies Peter De Schrijver
2012-01-31 15:44 ` Peter Zijlstra
2012-01-31 19:18   ` Diwakar Tundlam
2012-01-31 20:03     ` Peter Zijlstra
2012-01-31 19:23   ` Diwakar Tundlam
2012-01-31 20:02     ` Peter Zijlstra
2012-03-07 22:44       ` Diwakar Tundlam [this message]
2012-03-08 10:39         ` [PATCH] scheduler: domain: correctly initialize 'next_balance' in 'nohz' idle balancer Peter Zijlstra
2012-03-08 23:44         ` [PATCH] init: check printed flag to skip printing message Diwakar Tundlam
2012-03-09  0:07           ` Andrew Morton
2012-03-09  0:11           ` Joe Perches
2012-03-13  4:45         ` [tip:sched/core] sched/nohz: Correctly initialize 'next_balance' in 'nohz' idle balancer tip-bot for Diwakar Tundlam

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