Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1753386AbaKXKQb (ORCPT ); Mon, 24 Nov 2014 05:16:31 -0500 Received: from mail-ob0-f170.google.com ([209.85.214.170]:56866 "EHLO mail-ob0-f170.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1753347AbaKXKQa convert rfc822-to-8bit (ORCPT ); Mon, 24 Nov 2014 05:16:30 -0500 MIME-Version: 1.0 In-Reply-To: <54713254.9020601@gmail.com> References: <1412684017-16595-1-git-send-email-vincent.guittot@linaro.org> <1412684017-16595-7-git-send-email-vincent.guittot@linaro.org> <20141009121643.GQ4750@worktop.programming.kicks-ass.net> <54713254.9020601@gmail.com> From: Vincent Guittot Date: Mon, 24 Nov 2014 11:16:09 +0100 Message-ID: Subject: Re: [PATCH v7 6/7] sched: replace capacity_factor by usage To: Wanpeng Li Cc: Peter Zijlstra , Ingo Molnar , linux-kernel , Preeti U Murthy , Morten Rasmussen , Kamalesh Babulal , Russell King - ARM Linux , LAK , Rik van Riel , Mike Galbraith , Nicolas Pitre , "linaro-kernel@lists.linaro.org" , Daniel Lezcano , Dietmar Eggemann , Paul Turner , Benjamin Segall Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8BIT Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On 23 November 2014 at 02:03, Wanpeng Li wrote: > Hi Vincent, > On 10/9/14, 10:18 PM, Vincent Guittot wrote: >> >> On 9 October 2014 14:16, Peter Zijlstra wrote: >>> >>> On Tue, Oct 07, 2014 at 02:13:36PM +0200, Vincent Guittot wrote: >>>> >>>> +static inline bool >>>> +group_has_capacity(struct lb_env *env, struct sg_lb_stats *sgs) >>>> { >>>> + if ((sgs->group_capacity * 100) > >>>> + (sgs->group_usage * env->sd->imbalance_pct)) >>>> + return true; >>> >>> Why the imb_pct there? We're looking for 100% utilization, not 130 or >>> whatnot, right? >> >> Having exactly 100% is quite difficult because of various rounding. > > > Could you give some examples about the various rounding？ As an example while I was monitoring the runnable_load_sum and the runnable_load_period, they were varying a bit around the max value but was not always the same which can change the load_avg_contrib by few unit Regards, Vincent > > Regards, > Wanpeng Li > >> So i have added a margin/threshold to prevent any excessive change of the >> state. >> I have just to use the same margin/threshold than in other place in >> load balance. >> >> so the current threshold depends of the sched_level. it's around 14% at MC >> level >> >>>> + if (sgs->sum_nr_running < sgs->group_weight) >>>> + return true; >>> >>> With the code as it stands, this is the cheaper test (no mults) so why >>> is it second? >>> >>>> + return false; >>>> +} >>>> >>>> +static inline bool >>>> +group_is_overloaded(struct lb_env *env, struct sg_lb_stats *sgs) >>>> +{ >>>> + if (sgs->sum_nr_running <= sgs->group_weight) >>>> + return false; >>>> + >>>> + if ((sgs->group_capacity * 100) < >>>> + (sgs->group_usage * env->sd->imbalance_pct)) >>>> + return true; >>>> >>>> + return false; >>>> } >>> >>> Same thing here wrt imb_pct >> >> -- >> To unsubscribe from this list: send the line "unsubscribe linux-kernel" in >> the body of a message to majordomo@vger.kernel.org >> More majordomo info at http://vger.kernel.org/majordomo-info.html >> Please read the FAQ at http://www.tux.org/lkml/ > > -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/