From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1756946Ab3ILSGf (ORCPT ); Thu, 12 Sep 2013 14:06:35 -0400 Received: from terminus.zytor.com ([198.137.202.10]:37969 "EHLO terminus.zytor.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1756151Ab3ILSGc (ORCPT ); Thu, 12 Sep 2013 14:06:32 -0400 Date: Thu, 12 Sep 2013 11:05:56 -0700 From: tip-bot for Peter Zijlstra Message-ID: Cc: linux-kernel@vger.kernel.org, hpa@zytor.com, mingo@kernel.org, peterz@infradead.org, tglx@linutronix.de Reply-To: mingo@kernel.org, hpa@zytor.com, linux-kernel@vger.kernel.org, peterz@infradead.org, tglx@linutronix.de To: linux-tip-commits@vger.kernel.org Subject: [tip:sched/core] sched/fair: Rework and comment the group_capacity code Git-Commit-ID: b37d931685b519cd61a67fbdfe5b04707eb76e32 X-Mailer: tip-git-log-daemon Robot-ID: Robot-Unsubscribe: Contact to get blacklisted from these emails MIME-Version: 1.0 Content-Transfer-Encoding: 8bit Content-Type: text/plain; charset=UTF-8 Content-Disposition: inline X-Greylist: Sender IP whitelisted, not delayed by milter-greylist-4.2.7 (terminus.zytor.com [127.0.0.1]); Thu, 12 Sep 2013 11:06:03 -0700 (PDT) Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Commit-ID: b37d931685b519cd61a67fbdfe5b04707eb76e32 Gitweb: http://git.kernel.org/tip/b37d931685b519cd61a67fbdfe5b04707eb76e32 Author: Peter Zijlstra AuthorDate: Wed, 28 Aug 2013 11:50:34 +0200 Committer: Ingo Molnar CommitDate: Thu, 12 Sep 2013 19:14:44 +0200 sched/fair: Rework and comment the group_capacity code Pull out the group_capacity computation so that we can more clearly comment its issues. Signed-off-by: Peter Zijlstra Link: http://lkml.kernel.org/n/tip-az1hl1ya55k361nkeh9bj0yw@git.kernel.org Signed-off-by: Ingo Molnar --- kernel/sched/fair.c | 32 ++++++++++++++++++++++++-------- 1 file changed, 24 insertions(+), 8 deletions(-) diff --git a/kernel/sched/fair.c b/kernel/sched/fair.c index baba313..218f9c5 100644 --- a/kernel/sched/fair.c +++ b/kernel/sched/fair.c @@ -4553,6 +4553,27 @@ static inline int sg_imbalanced(struct sched_group *group) return group->sgp->imbalance; } +/* + * Compute the group capacity. + * + * For now the capacity is simply the number of power units in the group_power. + * A power unit represents a full core. + * + * This has an issue where N*frac(smt_power) >= 1, in that case we'll see extra + * 'cores' that aren't actually there. + */ +static inline int sg_capacity(struct lb_env *env, struct sched_group *group) +{ + + unsigned int power = group->sgp->power; + unsigned int capacity = DIV_ROUND_CLOSEST(power, SCHED_POWER_SCALE); + + if (!capacity) + capacity = fix_small_capacity(env->sd, group); + + return capacity; +} + /** * update_sg_lb_stats - Update sched_group's statistics for load balancing. * @env: The load balancing environment. @@ -4596,16 +4617,11 @@ static inline void update_sg_lb_stats(struct lb_env *env, if (sgs->sum_nr_running) sgs->load_per_task = sgs->sum_weighted_load / sgs->sum_nr_running; - sgs->group_imb = sg_imbalanced(group); - - sgs->group_capacity = - DIV_ROUND_CLOSEST(sgs->group_power, SCHED_POWER_SCALE); - - if (!sgs->group_capacity) - sgs->group_capacity = fix_small_capacity(env->sd, group); - sgs->group_weight = group->group_weight; + sgs->group_imb = sg_imbalanced(group); + sgs->group_capacity = sg_capacity(env, group); + if (sgs->group_capacity > sgs->sum_nr_running) sgs->group_has_capacity = 1; }