From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by smtp.lore.kernel.org (Postfix) with ESMTP id 5ECF8C433EF for ; Tue, 10 May 2022 15:15:31 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1345402AbiEJPTZ (ORCPT ); Tue, 10 May 2022 11:19:25 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:55654 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1345467AbiEJPTA (ORCPT ); Tue, 10 May 2022 11:19:00 -0400 Received: from foss.arm.com (foss.arm.com [217.140.110.172]) by lindbergh.monkeyblade.net (Postfix) with ESMTP id 043B41D6750 for ; Tue, 10 May 2022 07:56:29 -0700 (PDT) Received: from usa-sjc-imap-foss1.foss.arm.com (unknown [10.121.207.14]) by usa-sjc-mx-foss1.foss.arm.com (Postfix) with ESMTP id BF34012FC; Tue, 10 May 2022 07:56:28 -0700 (PDT) Received: from wubuntu (FVFF764EQ05P.cambridge.arm.com [10.1.34.46]) by usa-sjc-imap-foss1.foss.arm.com (Postfix) with ESMTPSA id 30F6F3F73D; Tue, 10 May 2022 07:56:27 -0700 (PDT) Date: Tue, 10 May 2022 15:56:25 +0100 From: Qais Yousef To: Xuewen Yan Cc: Xuewen Yan , dietmar.eggemann@arm.com, lukasz.luba@arm.com, rafael@kernel.org, viresh.kumar@linaro.org, mingo@redhat.com, peterz@infradead.org, vincent.guittot@linaro.org, rostedt@goodmis.org, linux-kernel@vger.kernel.org, di.shen@unisoc.com Subject: Re: [PATCH] sched: Take thermal pressure into account when determine rt fits capacity Message-ID: <20220510145625.t5py7atlhgojsfyf@wubuntu> References: <20220421161509.asz25zmh25eurgrk@airbuntu> <20220425161209.ydugtrs3b7gyy3kk@airbuntu> <20220426092142.lppfj5eqgt3d24nb@airbuntu> <20220427105844.otru4yohja4s23ye@wubuntu> <20220503144352.lxduzhl6jq6xdhw2@airbuntu> MIME-Version: 1.0 Content-Type: text/plain; charset=utf-8 Content-Disposition: inline In-Reply-To: Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Hi Xuewen On 05/09/22 10:29, Xuewen Yan wrote: [...] > > diff --git a/kernel/sched/fair.c b/kernel/sched/fair.c > > index a68482d66535..44c7c2598d87 100644 > > --- a/kernel/sched/fair.c > > +++ b/kernel/sched/fair.c > > @@ -8399,16 +8399,37 @@ static unsigned long scale_rt_capacity(int cpu) > > > > static void update_cpu_capacity(struct sched_domain *sd, int cpu) > > { > > + unsigned long capacity_orig = arch_scale_cpu_capacity(cpu); > > unsigned long capacity = scale_rt_capacity(cpu); > > struct sched_group *sdg = sd->groups; > > + struct rq *rq = cpu_rq(cpu); > > > > - cpu_rq(cpu)->cpu_capacity_orig = arch_scale_cpu_capacity(cpu); > > + rq->cpu_capacity_orig = capacity_orig; > > > > if (!capacity) > > capacity = 1; > > > > - cpu_rq(cpu)->cpu_capacity = capacity; > > - trace_sched_cpu_capacity_tp(cpu_rq(cpu)); > > + rq->cpu_capacity = capacity; > > + trace_sched_cpu_capacity_tp(rq); > > + > > + if (static_branch_unlikely(&sched_asym_cpucapacity)) { > > + unsigned long inv_cap = capacity_orig - thermal_load_avg(rq); > > Indeed, I prefer arch_thermal_pressure here, because the > thermal_load_avg would change over time, > but the inv_cap's update period may could not keep up with his changes. If that's what works for you, I think that's fine. Vincent, Lukasz you okay with that? > > > + > > + rq->cpu_capacity_inverted = 0; > > + > > + for_each_possible_cpu(cpu) { > > + unsigned long cap = arch_scale_cpu_capacity(cpu); > > + > > + if (capacity_orig <= cap) > > + continue; > > + > > + if (cap > inv_cap) { > > + rq->cpu_capacity_inverted = inv_cap; > > + break; > > + } > > + } > > + > > + } > > > > sdg->sgc->capacity = capacity; > > sdg->sgc->min_capacity = capacity; > > diff --git a/kernel/sched/sched.h b/kernel/sched/sched.h > > index 8dccb34eb190..bfe84c870bf9 100644 > > --- a/kernel/sched/sched.h > > +++ b/kernel/sched/sched.h > > @@ -992,6 +992,7 @@ struct rq { > > > > unsigned long cpu_capacity; > > unsigned long cpu_capacity_orig; > > + unsigned long cpu_capacity_inverted; > > > > struct callback_head *balance_callback; > > > > @@ -2807,6 +2808,11 @@ static inline unsigned long capacity_orig_of(int cpu) > > return cpu_rq(cpu)->cpu_capacity_orig; > > } > > > > +static inline unsigned long cpu_in_capacity_inversion(int cpu) > > +{ > > + return cpu_rq(cpu)->cpu_capacity_inverted; > > +} > > + > > /** > > * enum cpu_util_type - CPU utilization type > > * @FREQUENCY_UTIL: Utilization used to select frequency > > > > > > --->8--- > > The patch is amazing for me, and the complexity is not too high. Would > you please push the patch? > I think the idea is yours, I don't want to use it as my patch v2. I'd be happy to add a commit message so that you can include it in your v2. First, I'd like to hear from Vincent and Lukasz they're happy with this approach. I've been trying to think how we can do this generically but can't find an alternative to the extra loop or additional fallback_cpu_mask. Maybe the mask is okay if we protect it with sched_asymmetric_cpucapacity static key.. Thanks -- Qais Yousef