From patchwork Wed Aug 31 10:52:17 2016 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Morten Rasmussen X-Patchwork-Id: 75073 Delivered-To: patch@linaro.org Received: by 10.140.29.52 with SMTP id a49csp265035qga; Wed, 31 Aug 2016 03:52:45 -0700 (PDT) X-Received: by 10.98.28.142 with SMTP id c136mr15587330pfc.131.1472640757678; Wed, 31 Aug 2016 03:52:37 -0700 (PDT) Return-Path: Received: from vger.kernel.org (vger.kernel.org. [209.132.180.67]) by mx.google.com with ESMTP id cq3si50316738pad.61.2016.08.31.03.52.37; Wed, 31 Aug 2016 03:52:37 -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 S1760359AbcHaKw2 (ORCPT + 27 others); Wed, 31 Aug 2016 06:52:28 -0400 Received: from foss.arm.com ([217.140.101.70]:57632 "EHLO foss.arm.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1760243AbcHaKwW (ORCPT ); Wed, 31 Aug 2016 06:52:22 -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 0A251CE7; Wed, 31 Aug 2016 03:52:12 -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 093CB3F220; Wed, 31 Aug 2016 03:52:09 -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 v4 3/5] sched: Add per-cpu min capacity to sched_group_capacity Date: Wed, 31 Aug 2016 11:52:17 +0100 Message-Id: <1472640739-8778-4-git-send-email-morten.rasmussen@arm.com> X-Mailer: git-send-email 1.9.1 In-Reply-To: <1472640739-8778-1-git-send-email-morten.rasmussen@arm.com> References: <1472640739-8778-1-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 struct sched_group_capacity currently represents the compute capacity sum of all cpus in the sched_group. Unless it is divided by the group_weight to get the average capacity per cpu it hides differences in cpu capacity for mixed capacity systems (e.g. high RT/IRQ utilization or ARM big.LITTLE). But even the average may not be sufficient if the group covers cpus of different capacities. Instead, by extending struct sched_group_capacity to indicate min per-cpu capacity in the group a suitable group for a given task utilization can more easily be found such that cpus with reduced capacity can be avoided for tasks with high utilization (not implemented by this patch). cc: Ingo Molnar cc: Peter Zijlstra Signed-off-by: Morten Rasmussen --- kernel/sched/core.c | 3 ++- kernel/sched/fair.c | 17 ++++++++++++----- kernel/sched/sched.h | 3 ++- 3 files changed, 16 insertions(+), 7 deletions(-) -- 1.9.1 diff --git a/kernel/sched/core.c b/kernel/sched/core.c index 69243142cad1..4df35c448f41 100644 --- a/kernel/sched/core.c +++ b/kernel/sched/core.c @@ -5656,7 +5656,7 @@ static int sched_domain_debug_one(struct sched_domain *sd, int cpu, int level, printk(KERN_CONT " %*pbl", cpumask_pr_args(sched_group_cpus(group))); if (group->sgc->capacity != SCHED_CAPACITY_SCALE) { - printk(KERN_CONT " (cpu_capacity = %d)", + printk(KERN_CONT " (cpu_capacity = %lu)", group->sgc->capacity); } @@ -6125,6 +6125,7 @@ build_overlap_sched_groups(struct sched_domain *sd, int cpu) * die on a /0 trap. */ sg->sgc->capacity = SCHED_CAPACITY_SCALE * cpumask_weight(sg_span); + sg->sgc->min_capacity = SCHED_CAPACITY_SCALE; /* * Make sure the first group of this domain contains the diff --git a/kernel/sched/fair.c b/kernel/sched/fair.c index ebe8907119b5..112a6d3f3943 100644 --- a/kernel/sched/fair.c +++ b/kernel/sched/fair.c @@ -6714,13 +6714,14 @@ static void update_cpu_capacity(struct sched_domain *sd, int cpu) cpu_rq(cpu)->cpu_capacity = capacity; sdg->sgc->capacity = capacity; + sdg->sgc->min_capacity = capacity; } void update_group_capacity(struct sched_domain *sd, int cpu) { struct sched_domain *child = sd->child; struct sched_group *group, *sdg = sd->groups; - unsigned long capacity; + unsigned long capacity, min_capacity; unsigned long interval; interval = msecs_to_jiffies(sd->balance_interval); @@ -6733,6 +6734,7 @@ void update_group_capacity(struct sched_domain *sd, int cpu) } capacity = 0; + min_capacity = ULONG_MAX; if (child->flags & SD_OVERLAP) { /* @@ -6757,11 +6759,12 @@ void update_group_capacity(struct sched_domain *sd, int cpu) */ if (unlikely(!rq->sd)) { capacity += capacity_of(cpu); - continue; + } else { + sgc = rq->sd->groups->sgc; + capacity += sgc->capacity; } - sgc = rq->sd->groups->sgc; - capacity += sgc->capacity; + min_capacity = min(capacity, min_capacity); } } else { /* @@ -6771,12 +6774,16 @@ void update_group_capacity(struct sched_domain *sd, int cpu) group = child->groups; do { - capacity += group->sgc->capacity; + struct sched_group_capacity *sgc = group->sgc; + + capacity += sgc->capacity; + min_capacity = min(sgc->min_capacity, min_capacity); group = group->next; } while (group != child->groups); } sdg->sgc->capacity = capacity; + sdg->sgc->min_capacity = min_capacity; } /* diff --git a/kernel/sched/sched.h b/kernel/sched/sched.h index 420c05d099c3..ef646f542994 100644 --- a/kernel/sched/sched.h +++ b/kernel/sched/sched.h @@ -868,7 +868,8 @@ struct sched_group_capacity { * CPU capacity of this group, SCHED_CAPACITY_SCALE being max capacity * for a single CPU. */ - unsigned int capacity; + unsigned long capacity; + unsigned long min_capacity; /* Min per-cpu capacity in group */ unsigned long next_update; int imbalance; /* XXX unrelated to capacity but shared group state */ /*