From patchwork Mon Jul 25 13:34:26 2016 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Morten Rasmussen X-Patchwork-Id: 72728 Delivered-To: patch@linaro.org Received: by 10.140.29.52 with SMTP id a49csp1151742qga; Mon, 25 Jul 2016 06:37:22 -0700 (PDT) X-Received: by 10.66.148.7 with SMTP id to7mr30239659pab.128.1469453842310; Mon, 25 Jul 2016 06:37:22 -0700 (PDT) Return-Path: Received: from vger.kernel.org (vger.kernel.org. [209.132.180.67]) by mx.google.com with ESMTP id mu1si27359182pab.286.2016.07.25.06.37.19; Mon, 25 Jul 2016 06:37:22 -0700 (PDT) Received-SPF: pass (google.com: best guess record for domain of linux-kernel-owner@vger.kernel.org designates 209.132.180.67 as permitted sender) client-ip=209.132.180.67; Authentication-Results: mx.google.com; spf=pass (google.com: best guess record for domain of linux-kernel-owner@vger.kernel.org designates 209.132.180.67 as permitted sender) smtp.mailfrom=linux-kernel-owner@vger.kernel.org Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1753205AbcGYNhR (ORCPT + 29 others); Mon, 25 Jul 2016 09:37:17 -0400 Received: from foss.arm.com ([217.140.101.70]:33751 "EHLO foss.arm.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1752657AbcGYNfQ (ORCPT ); Mon, 25 Jul 2016 09:35:16 -0400 Received: from usa-sjc-imap-foss1.foss.arm.com (unknown [10.72.51.249]) by usa-sjc-mx-foss1.foss.arm.com (Postfix) with ESMTP id 3DC07BB0; Mon, 25 Jul 2016 06:36:30 -0700 (PDT) Received: from e105550-lin.cambridge.arm.com (e105550-lin.cambridge.arm.com [10.1.211.30]) by usa-sjc-imap-foss1.foss.arm.com (Postfix) with ESMTPA id C8A313F21A; Mon, 25 Jul 2016 06:35:13 -0700 (PDT) From: Morten Rasmussen To: peterz@infradead.org, mingo@redhat.com Cc: dietmar.eggemann@arm.com, yuyang.du@intel.com, vincent.guittot@linaro.org, mgalbraith@suse.de, sgurrappadi@nvidia.com, freedom.tan@mediatek.com, keita.kobayashi.ym@renesas.com, linux-kernel@vger.kernel.org, Morten Rasmussen Subject: [PATCH v3 09/13] sched/fair: Let asymmetric cpu configurations balance at wake-up Date: Mon, 25 Jul 2016 14:34:26 +0100 Message-Id: <1469453670-2660-10-git-send-email-morten.rasmussen@arm.com> X-Mailer: git-send-email 1.9.1 In-Reply-To: <1469453670-2660-1-git-send-email-morten.rasmussen@arm.com> References: <1469453670-2660-1-git-send-email-morten.rasmussen@arm.com> Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Currently, SD_WAKE_AFFINE always takes priority over wakeup balancing if SD_BALANCE_WAKE is set on the sched_domains. For asymmetric configurations SD_WAKE_AFFINE is only desirable if the waking task's compute demand (utilization) is suitable for the waking cpu and the previous cpu, and all cpus within their respective SD_SHARE_PKG_RESOURCES domains (sd_llc). If not, let wakeup balancing take over (find_idlest_{group, cpu}()). This patch makes affine wake-ups conditional on whether both the waker cpu and prev_cpu has sufficient capacity for the waking task, or not, assuming that the cpu capacities within an SD_SHARE_PKG_RESOURCES domain (sd_llc) are homogeneous. cc: Ingo Molnar cc: Peter Zijlstra Acked-by: Vincent Guittot Signed-off-by: Morten Rasmussen --- kernel/sched/fair.c | 28 +++++++++++++++++++++++++++- 1 file changed, 27 insertions(+), 1 deletion(-) -- 1.9.1 diff --git a/kernel/sched/fair.c b/kernel/sched/fair.c index c1c0aa8b300b..9e217eff3daf 100644 --- a/kernel/sched/fair.c +++ b/kernel/sched/fair.c @@ -114,6 +114,12 @@ unsigned int __read_mostly sysctl_sched_shares_window = 10000000UL; unsigned int sysctl_sched_cfs_bandwidth_slice = 5000UL; #endif +/* + * The margin used when comparing utilization with cpu capacity: + * util * 1024 < capacity * margin + */ +unsigned int capacity_margin = 1280; /* ~20% */ + static inline void update_load_add(struct load_weight *lw, unsigned long inc) { lw->weight += inc; @@ -5366,6 +5372,25 @@ static int cpu_util(int cpu) return (util >= capacity) ? capacity : util; } +static inline int task_util(struct task_struct *p) +{ + return p->se.avg.util_avg; +} + +static int wake_cap(struct task_struct *p, int cpu, int prev_cpu) +{ + long min_cap, max_cap; + + min_cap = min(capacity_orig_of(prev_cpu), capacity_orig_of(cpu)); + max_cap = cpu_rq(cpu)->rd->max_cpu_capacity; + + /* Minimum capacity is close to max, no need to abort wake_affine */ + if (max_cap - min_cap < max_cap >> 3) + return 0; + + return min_cap * 1024 < task_util(p) * capacity_margin; +} + /* * select_task_rq_fair: Select target runqueue for the waking task in domains * that have the 'sd_flag' flag set. In practice, this is SD_BALANCE_WAKE, @@ -5389,7 +5414,8 @@ select_task_rq_fair(struct task_struct *p, int prev_cpu, int sd_flag, int wake_f if (sd_flag & SD_BALANCE_WAKE) { record_wakee(p); - want_affine = !wake_wide(p) && cpumask_test_cpu(cpu, tsk_cpus_allowed(p)); + want_affine = !wake_wide(p) && !wake_cap(p, cpu, prev_cpu) + && cpumask_test_cpu(cpu, tsk_cpus_allowed(p)); } rcu_read_lock();