Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1751252AbbFXHLs (ORCPT ); Wed, 24 Jun 2015 03:11:48 -0400 Received: from mail-wg0-f44.google.com ([74.125.82.44]:34913 "EHLO mail-wg0-f44.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1750953AbbFXHLk (ORCPT ); Wed, 24 Jun 2015 03:11:40 -0400 From: Vincent Guittot To: yuyang.du@intel.com, linux-kernel@vger.kernel.org, mingo@kernel.org, peterz@infradead.org Cc: pjt@google.com, bsegall@google.com, morten.rasmussen@arm.com, dietmar.eggemann@arm.com, len.brown@intel.com, rafael.j.wysocki@intel.com, fengguang.wu@intel.com, boqun.feng@gmail.com, srikar@linux.vnet.ibm.com, Vincent Guittot Subject: [PATCH] sched: update blocked load of idle cpus Date: Wed, 24 Jun 2015 09:11:12 +0200 Message-Id: <1435129872-22915-1-git-send-email-vincent.guittot@linaro.org> X-Mailer: git-send-email 1.9.1 In-Reply-To: <1435018085-7004-3-git-send-email-yuyang.du@intel.com> References: <1435018085-7004-3-git-send-email-yuyang.du@intel.com> Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 1642 Lines: 54 The load and the util of idle cpus must be updated periodically in order to decay the blocked part. If CONFIG_FAIR_GROUP_SCHED is not set, the load and util of idle cpus are not decayed and stay at the values set before becoming idle. Signed-off-by: Vincent Guittot --- Hi Yuyang, While testing your patchset without CONFIG_FAIR_GROUP_SCHED, i have noticed that the load of idle cpus stays sometimes to an high value whereas they were not used for a while because we are not decaying the blocked load. Futhermore, the peridodic load balance was not pulling tasks onto some idle cpus because their load stayed high. This patchset fixes the issue. Regards, Vincent kernel/sched/fair.c | 11 +++++++++++ 1 file changed, 11 insertions(+) diff --git a/kernel/sched/fair.c b/kernel/sched/fair.c index c5f18d9..665cc4b 100644 --- a/kernel/sched/fair.c +++ b/kernel/sched/fair.c @@ -5864,6 +5864,17 @@ static unsigned long task_h_load(struct task_struct *p) #else static inline void update_blocked_averages(int cpu) { + struct rq *rq = cpu_rq(cpu); + struct cfs_rq *cfs_rq = &rq->cfs; + unsigned long flags; + + raw_spin_lock_irqsave(&rq->lock, flags); + update_rq_clock(rq); + + update_cfs_rq_load_avg(cfs_rq_clock_task(cfs_rq), cfs_rq)) + + raw_spin_unlock_irqrestore(&rq->lock, flags); + } static unsigned long task_h_load(struct task_struct *p) -- 1.9.1 -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/