From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1757163Ab0DWKuk (ORCPT ); Fri, 23 Apr 2010 06:50:40 -0400 Received: from hera.kernel.org ([140.211.167.34]:40702 "EHLO hera.kernel.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1757149Ab0DWKuh (ORCPT ); Fri, 23 Apr 2010 06:50:37 -0400 Date: Fri, 23 Apr 2010 10:50:16 GMT From: tip-bot for Peter Zijlstra Cc: linux-kernel@vger.kernel.org, hpa@zytor.com, mingo@redhat.com, a.p.zijlstra@chello.nl, tglx@linutronix.de, mingo@elte.hu, davem@davemloft.net Reply-To: mingo@redhat.com, hpa@zytor.com, linux-kernel@vger.kernel.org, a.p.zijlstra@chello.nl, tglx@linutronix.de, davem@davemloft.net, mingo@elte.hu In-Reply-To: References: To: linux-tip-commits@vger.kernel.org Subject: [tip:sched/core] sched: Pre-compute cpumask_weight(sched_domain_span(sd)) Message-ID: Git-Commit-ID: 669c55e9f99b90e46eaa0f98a67ec53d46dc969a X-Mailer: tip-git-log-daemon MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Disposition: inline X-Greylist: Sender IP whitelisted, not delayed by milter-greylist-4.2.3 (hera.kernel.org [127.0.0.1]); Fri, 23 Apr 2010 10:50:16 +0000 (UTC) Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Commit-ID: 669c55e9f99b90e46eaa0f98a67ec53d46dc969a Gitweb: http://git.kernel.org/tip/669c55e9f99b90e46eaa0f98a67ec53d46dc969a Author: Peter Zijlstra AuthorDate: Fri, 16 Apr 2010 14:59:29 +0200 Committer: Ingo Molnar CommitDate: Fri, 23 Apr 2010 11:02:02 +0200 sched: Pre-compute cpumask_weight(sched_domain_span(sd)) Dave reported that his large SPARC machines spend lots of time in hweight64(), try and optimize some of those needless cpumask_weight() invocations (esp. with the large offstack cpumasks these are very expensive indeed). Reported-by: David Miller Signed-off-by: Peter Zijlstra LKML-Reference: Signed-off-by: Ingo Molnar --- include/linux/sched.h | 1 + kernel/sched.c | 3 +++ kernel/sched_fair.c | 12 +++++------- 3 files changed, 9 insertions(+), 7 deletions(-) diff --git a/include/linux/sched.h b/include/linux/sched.h index e3e900f..dfea405 100644 --- a/include/linux/sched.h +++ b/include/linux/sched.h @@ -960,6 +960,7 @@ struct sched_domain { char *name; #endif + unsigned int span_weight; /* * Span of all CPUs in this domain. * diff --git a/kernel/sched.c b/kernel/sched.c index 0cc913a..4956ed0 100644 --- a/kernel/sched.c +++ b/kernel/sched.c @@ -6271,6 +6271,9 @@ cpu_attach_domain(struct sched_domain *sd, struct root_domain *rd, int cpu) struct rq *rq = cpu_rq(cpu); struct sched_domain *tmp; + for (tmp = sd; tmp; tmp = tmp->parent) + tmp->span_weight = cpumask_weight(sched_domain_span(tmp)); + /* Remove the sched domains which do not contribute to scheduling. */ for (tmp = sd; tmp; ) { struct sched_domain *parent = tmp->parent; diff --git a/kernel/sched_fair.c b/kernel/sched_fair.c index 88d3053..0a413c7 100644 --- a/kernel/sched_fair.c +++ b/kernel/sched_fair.c @@ -1508,9 +1508,7 @@ select_task_rq_fair(struct rq *rq, struct task_struct *p, int sd_flag, int wake_ * Pick the largest domain to update shares over */ tmp = sd; - if (affine_sd && (!tmp || - cpumask_weight(sched_domain_span(affine_sd)) > - cpumask_weight(sched_domain_span(sd)))) + if (affine_sd && (!tmp || affine_sd->span_weight > sd->span_weight)) tmp = affine_sd; if (tmp) { @@ -1554,10 +1552,10 @@ select_task_rq_fair(struct rq *rq, struct task_struct *p, int sd_flag, int wake_ /* Now try balancing at a lower domain level of new_cpu */ cpu = new_cpu; - weight = cpumask_weight(sched_domain_span(sd)); + weight = sd->span_weight; sd = NULL; for_each_domain(cpu, tmp) { - if (weight <= cpumask_weight(sched_domain_span(tmp))) + if (weight <= tmp->span_weight) break; if (tmp->flags & sd_flag) sd = tmp; @@ -2243,7 +2241,7 @@ unsigned long __weak arch_scale_freq_power(struct sched_domain *sd, int cpu) unsigned long default_scale_smt_power(struct sched_domain *sd, int cpu) { - unsigned long weight = cpumask_weight(sched_domain_span(sd)); + unsigned long weight = sd->span_weight; unsigned long smt_gain = sd->smt_gain; smt_gain /= weight; @@ -2276,7 +2274,7 @@ unsigned long scale_rt_power(int cpu) static void update_cpu_power(struct sched_domain *sd, int cpu) { - unsigned long weight = cpumask_weight(sched_domain_span(sd)); + unsigned long weight = sd->span_weight; unsigned long power = SCHED_LOAD_SCALE; struct sched_group *sdg = sd->groups;