From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S964968AbaE3TOV (ORCPT ); Fri, 30 May 2014 15:14:21 -0400 Received: from mail-ob0-f172.google.com ([209.85.214.172]:46436 "EHLO mail-ob0-f172.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1753146AbaE3TOU (ORCPT ); Fri, 30 May 2014 15:14:20 -0400 MIME-Version: 1.0 In-Reply-To: <20140530063402.GB11096@twins.programming.kicks-ass.net> References: <1400860385-14555-1-git-send-email-vincent.guittot@linaro.org> <1400860385-14555-12-git-send-email-vincent.guittot@linaro.org> <20140529140204.GH11074@laptop.programming.kicks-ass.net> <20140530063402.GB11096@twins.programming.kicks-ass.net> From: Vincent Guittot Date: Fri, 30 May 2014 21:13:59 +0200 Message-ID: Subject: Re: [PATCH v2 11/11] sched: replace capacity by activity To: Peter Zijlstra Cc: Ingo Molnar , linux-kernel , Russell King - ARM Linux , LAK , Preeti U Murthy , Morten Rasmussen , Mike Galbraith , Nicolas Pitre , "linaro-kernel@lists.linaro.org" , Daniel Lezcano Content-Type: text/plain; charset=ISO-8859-1 Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On 30 May 2014 08:34, Peter Zijlstra wrote: > On Thu, May 29, 2014 at 09:56:24PM +0200, Vincent Guittot wrote: >> On 29 May 2014 16:02, Peter Zijlstra wrote: >> > On Fri, May 23, 2014 at 05:53:05PM +0200, Vincent Guittot wrote: >> >> @@ -6052,8 +6006,8 @@ static inline void update_sd_lb_stats(struct lb_env *env, struct sd_lb_stats *sd >> >> * with a large weight task outweighs the tasks on the system). >> >> */ >> >> if (prefer_sibling && sds->local && >> >> - sds->local_stat.group_has_capacity) >> >> - sgs->group_capacity = min(sgs->group_capacity, 1U); >> >> + sds->local_stat.group_capacity > 0) >> >> + sgs->group_capacity = min(sgs->group_capacity, 1L); >> >> >> >> if (update_sd_pick_busiest(env, sds, sg, sgs)) { >> >> sds->busiest = sg; >> >> @@ -6228,7 +6182,7 @@ static inline void calculate_imbalance(struct lb_env *env, struct sd_lb_stats *s >> >> * have to drop below capacity to reach cpu-load equilibrium. >> >> */ >> >> load_above_capacity = >> >> - (busiest->sum_nr_running - busiest->group_capacity); >> >> + (busiest->sum_nr_running - busiest->group_weight); >> >> >> >> load_above_capacity *= (SCHED_LOAD_SCALE * SCHED_POWER_SCALE); >> >> load_above_capacity /= busiest->group_power; >> > >> > I think you just broke PREFER_SIBLING here.. >> >> you mean by replacing the capacity which was reflecting the number of >> core for SMT by the group_weight ? > > Right to in the first hunk we lower group_capacity to 1 when prefer_sibling, > then in the second hunk, you replace that group_capacity usage with > group_weight. > > With the end result that prefer_sibling is now ineffective. ok > > That said, I fudged the prefer_sibling usage into the capacity logic, > mostly because I could and it was already how the SMT stuff was working. > But there is no reason we should continue to intertwine these two > things. > > So I think it would be good to have a patch that implements > prefer_sibling on nr_running separate from the existing capacity bits, > and then convert the remaining capacity bits to utilization (or activity > or whatever you did call it, see Morton's comments etc.). ok, i'm going to prepare such change > >