From patchwork Wed Jun 25 00:36:07 2014 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Yuyang Du X-Patchwork-Id: 4417441 Return-Path: X-Original-To: patchwork-linux-pm@patchwork.kernel.org Delivered-To: patchwork-parsemail@patchwork1.web.kernel.org Received: from mail.kernel.org (mail.kernel.org [198.145.19.201]) by patchwork1.web.kernel.org (Postfix) with ESMTP id EC8449F1D6 for ; Wed, 25 Jun 2014 08:42:44 +0000 (UTC) Received: from mail.kernel.org (localhost [127.0.0.1]) by mail.kernel.org (Postfix) with ESMTP id 0AED22038F for ; Wed, 25 Jun 2014 08:42:44 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id 0F39C20386 for ; Wed, 25 Jun 2014 08:42:43 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1755957AbaFYIkh (ORCPT ); Wed, 25 Jun 2014 04:40:37 -0400 Received: from mga03.intel.com ([143.182.124.21]:15876 "EHLO mga03.intel.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1755811AbaFYIkc (ORCPT ); Wed, 25 Jun 2014 04:40:32 -0400 Received: from azsmga001.ch.intel.com ([10.2.17.19]) by azsmga101.ch.intel.com with ESMTP; 25 Jun 2014 01:40:21 -0700 X-ExtLoop1: 1 X-IronPort-AV: E=Sophos;i="5.01,544,1400050800"; d="scan'208";a="449717545" Received: from dalvikqa005-desktop.bj.intel.com ([10.238.151.105]) by azsmga001.ch.intel.com with ESMTP; 25 Jun 2014 01:40:16 -0700 From: Yuyang Du To: mingo@redhat.com, peterz@infradead.org, rafael.j.wysocki@intel.com, linux-kernel@vger.kernel.org, linux-pm@vger.kernel.org Cc: arjan.van.de.ven@intel.com, len.brown@intel.com, alan.cox@intel.com, mark.gross@intel.com, morten.rasmussen@arm.com, vincent.guittot@linaro.org, dietmar.eggemann@arm.com, rajeev.d.muralidhar@intel.com, vishwesh.m.rudramuni@intel.com, nicole.chalhoub@intel.com, ajaya.durg@intel.com, harinarayanan.seshadri@intel.com, jacob.jun.pan@linux.intel.com, Yuyang Du Subject: [RFC PATCH 8/9 v4] Implement Workload Consolidation in nohz_idle_balance Date: Wed, 25 Jun 2014 08:36:07 +0800 Message-Id: <1403656568-32445-9-git-send-email-yuyang.du@intel.com> X-Mailer: git-send-email 1.7.9.5 In-Reply-To: <1403656568-32445-1-git-send-email-yuyang.du@intel.com> References: <1403656568-32445-1-git-send-email-yuyang.du@intel.com> Sender: linux-pm-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-pm@vger.kernel.org X-Spam-Status: No, score=-5.4 required=5.0 tests=BAYES_00, DATE_IN_PAST_06_12, RCVD_IN_DNSWL_HI, T_RP_MATCHES_RCVD, UNPARSEABLE_RELAY autolearn=unavailable version=3.3.1 X-Spam-Checker-Version: SpamAssassin 3.3.1 (2010-03-16) on mail.kernel.org X-Virus-Scanned: ClamAV using ClamSMTP In periodic nohz idle balance, we skip kicking idle but non-consolidated CPUs. Signed-off-by: Yuyang Du --- kernel/sched/fair.c | 55 +++++++++++++++++++++++++++++++++++++++++---------- 1 file changed, 45 insertions(+), 10 deletions(-) diff --git a/kernel/sched/fair.c b/kernel/sched/fair.c index bf65fde..549f6e0 100644 --- a/kernel/sched/fair.c +++ b/kernel/sched/fair.c @@ -6983,10 +6983,45 @@ static struct { static inline int find_new_ilb(void) { - int ilb = cpumask_first(nohz.idle_cpus_mask); + int ilb; - if (ilb < nr_cpu_ids && idle_cpu(ilb)) - return ilb; + /* + * Optimize for the case when we have no idle CPUs or only one + * idle CPU. Don't walk the sched_domain hierarchy in such cases + */ + if (cpumask_weight(nohz.idle_cpus_mask) < 2) + return nr_cpu_ids; + + ilb = cpumask_first(nohz.idle_cpus_mask); + + if (ilb < nr_cpu_ids && idle_cpu(ilb)) { + struct sched_domain *sd; + int this_cpu = smp_processor_id(); + + sd = per_cpu(sd_wc, this_cpu); + if (sd) { + struct cpumask *nonshielded_cpus = __get_cpu_var(load_balance_mask); + + cpumask_copy(nonshielded_cpus, nohz.idle_cpus_mask); + + rcu_read_lock(); + wc_nonshielded_mask(this_cpu, sd, nonshielded_cpus); + rcu_read_unlock(); + + if (cpumask_weight(nonshielded_cpus) < 2) + return nr_cpu_ids; + + /* + * get idle load balancer again + */ + ilb = cpumask_first(nonshielded_cpus); + + if (ilb < nr_cpu_ids && idle_cpu(ilb)) + return ilb; + } + else + return ilb; + } return nr_cpu_ids; } @@ -7217,7 +7252,7 @@ out: * In CONFIG_NO_HZ_COMMON case, the idle balance kickee will do the * rebalancing for all the cpus for whom scheduler ticks are stopped. */ -static void nohz_idle_balance(struct rq *this_rq, enum cpu_idle_type idle) +static void nohz_idle_balance(struct rq *this_rq, enum cpu_idle_type idle, struct cpumask *mask) { int this_cpu = this_rq->cpu; struct rq *rq; @@ -7227,7 +7262,7 @@ static void nohz_idle_balance(struct rq *this_rq, enum cpu_idle_type idle) !test_bit(NOHZ_BALANCE_KICK, nohz_flags(this_cpu))) goto end; - for_each_cpu(balance_cpu, nohz.idle_cpus_mask) { + for_each_cpu(balance_cpu, mask) { if (balance_cpu == this_cpu || !idle_cpu(balance_cpu)) continue; @@ -7280,10 +7315,10 @@ static inline int nohz_kick_needed(struct rq *rq) if (unlikely(rq->idle_balance)) return 0; - /* - * We may be recently in ticked or tickless idle mode. At the first - * busy tick after returning from idle, we will update the busy stats. - */ + /* + * We may be recently in ticked or tickless idle mode. At the first + * busy tick after returning from idle, we will update the busy stats. + */ set_cpu_sd_state_busy(); nohz_balance_exit_idle(cpu); @@ -7326,7 +7361,7 @@ need_kick: return 1; } #else -static void nohz_idle_balance(struct rq *this_rq, enum cpu_idle_type idle) { } +static void nohz_idle_balance(struct rq *this_rq, enum cpu_idle_type idle, struct cpumask *mask) { } #endif /*