From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1756978AbaISLtb (ORCPT ); Fri, 19 Sep 2014 07:49:31 -0400 Received: from terminus.zytor.com ([198.137.202.10]:56333 "EHLO terminus.zytor.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S932362AbaISLtK (ORCPT ); Fri, 19 Sep 2014 07:49:10 -0400 Date: Fri, 19 Sep 2014 04:48:22 -0700 From: tip-bot for Vincent Guittot Message-ID: Cc: linux-kernel@vger.kernel.org, hpa@zytor.com, mingo@kernel.org, torvalds@linux-foundation.org, peterz@infradead.org, vincent.guittot@linaro.org, tglx@linutronix.de Reply-To: mingo@kernel.org, hpa@zytor.com, linux-kernel@vger.kernel.org, torvalds@linux-foundation.org, peterz@infradead.org, vincent.guittot@linaro.org, tglx@linutronix.de In-Reply-To: <1409051215-16788-8-git-send-email-vincent.guittot@linaro.org> References: <1409051215-16788-8-git-send-email-vincent.guittot@linaro.org> To: linux-tip-commits@vger.kernel.org Subject: [tip:sched/core] sched: Test the CPU's capacity in wake_affine() Git-Commit-ID: bd61c98f9b3f142cd63f9e15acfe203bec9e5f5a X-Mailer: tip-git-log-daemon Robot-ID: Robot-Unsubscribe: Contact to get blacklisted from these emails MIME-Version: 1.0 Content-Transfer-Encoding: 8bit Content-Type: text/plain; charset=UTF-8 Content-Disposition: inline Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Commit-ID: bd61c98f9b3f142cd63f9e15acfe203bec9e5f5a Gitweb: http://git.kernel.org/tip/bd61c98f9b3f142cd63f9e15acfe203bec9e5f5a Author: Vincent Guittot AuthorDate: Tue, 26 Aug 2014 13:06:50 +0200 Committer: Ingo Molnar CommitDate: Fri, 19 Sep 2014 12:35:28 +0200 sched: Test the CPU's capacity in wake_affine() Currently the task always wakes affine on this_cpu if the latter is idle. Before waking up the task on this_cpu, we check that this_cpu capacity is not significantly reduced because of RT tasks or irq activity. Use case where the number of irq and/or the time spent under irq is important will take benefit of this because the task that is woken up by irq or softirq will not use the same CPU than irq (and softirq) but a idle one. Signed-off-by: Vincent Guittot Signed-off-by: Peter Zijlstra (Intel) Cc: preeti@linux.vnet.ibm.com Cc: riel@redhat.com Cc: Morten.Rasmussen@arm.com Cc: efault@gmx.de Cc: nicolas.pitre@linaro.org Cc: daniel.lezcano@linaro.org Cc: dietmar.eggemann@arm.com Cc: Linus Torvalds Link: http://lkml.kernel.org/r/1409051215-16788-8-git-send-email-vincent.guittot@linaro.org Signed-off-by: Ingo Molnar --- kernel/sched/fair.c | 19 ++++++++++--------- 1 file changed, 10 insertions(+), 9 deletions(-) diff --git a/kernel/sched/fair.c b/kernel/sched/fair.c index be530e4..74fa2c2 100644 --- a/kernel/sched/fair.c +++ b/kernel/sched/fair.c @@ -4284,6 +4284,7 @@ static int wake_wide(struct task_struct *p) static int wake_affine(struct sched_domain *sd, struct task_struct *p, int sync) { s64 this_load, load; + s64 this_eff_load, prev_eff_load; int idx, this_cpu, prev_cpu; struct task_group *tg; unsigned long weight; @@ -4327,21 +4328,21 @@ static int wake_affine(struct sched_domain *sd, struct task_struct *p, int sync) * Otherwise check if either cpus are near enough in load to allow this * task to be woken on this_cpu. */ - if (this_load > 0) { - s64 this_eff_load, prev_eff_load; + this_eff_load = 100; + this_eff_load *= capacity_of(prev_cpu); + + prev_eff_load = 100 + (sd->imbalance_pct - 100) / 2; + prev_eff_load *= capacity_of(this_cpu); - this_eff_load = 100; - this_eff_load *= capacity_of(prev_cpu); + if (this_load > 0) { this_eff_load *= this_load + effective_load(tg, this_cpu, weight, weight); - prev_eff_load = 100 + (sd->imbalance_pct - 100) / 2; - prev_eff_load *= capacity_of(this_cpu); prev_eff_load *= load + effective_load(tg, prev_cpu, 0, weight); + } + + balanced = this_eff_load <= prev_eff_load; - balanced = this_eff_load <= prev_eff_load; - } else - balanced = true; schedstat_inc(p, se.statistics.nr_wakeups_affine_attempts); if (!balanced)