Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1755992AbcJNNnM (ORCPT ); Fri, 14 Oct 2016 09:43:12 -0400 Received: from foss.arm.com ([217.140.101.70]:37682 "EHLO foss.arm.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1756322AbcJNNmO (ORCPT ); Fri, 14 Oct 2016 09:42:14 -0400 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 v5 3/6] sched: Add per-cpu min capacity to sched_group_capacity Date: Fri, 14 Oct 2016 14:41:09 +0100 Message-Id: <1476452472-24740-4-git-send-email-morten.rasmussen@arm.com> X-Mailer: git-send-email 2.7.4 In-Reply-To: <1476452472-24740-1-git-send-email-morten.rasmussen@arm.com> References: <1476452472-24740-1-git-send-email-morten.rasmussen@arm.com> Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 3995 Lines: 120 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(-) diff --git a/kernel/sched/core.c b/kernel/sched/core.c index aae08cedd75e..50526a20ab94 100644 --- a/kernel/sched/core.c +++ b/kernel/sched/core.c @@ -5703,7 +5703,7 @@ 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); } @@ -6180,6 +6180,7 @@ 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 cf84e37b3b4a..28e42cb41d7b 100644 --- a/kernel/sched/fair.c +++ b/kernel/sched/fair.c @@ -6905,13 +6905,14 @@ 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); @@ -6924,6 +6925,7 @@ void update_group_capacity(struct sched_domain *sd, int cpu) } capacity = 0; + min_capacity = ULONG_MAX; if (child->flags & SD_OVERLAP) { /* @@ -6948,11 +6950,12 @@ 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 { /* @@ -6962,12 +6965,16 @@ 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 19b99869809d..b3b3ecbbb494 100644 --- a/kernel/sched/sched.h +++ b/kernel/sched/sched.h @@ -892,7 +892,8 @@ 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 */ -- 2.7.4