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 X-Spam-Level: X-Spam-Status: No, score=-10.3 required=3.0 tests=BAYES_00, HEADER_FROM_DIFFERENT_DOMAINS,INCLUDES_PATCH,MAILING_LIST_MULTI,SPF_HELO_NONE, SPF_PASS,USER_AGENT_SANE_1 autolearn=unavailable autolearn_force=no version=3.4.0 Received: from mail.kernel.org (mail.kernel.org [198.145.29.99]) by smtp.lore.kernel.org (Postfix) with ESMTP id C8E14C47089 for ; Wed, 26 May 2021 21:43:15 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 9D66461057 for ; Wed, 26 May 2021 21:43:15 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S234070AbhEZVoq (ORCPT ); Wed, 26 May 2021 17:44:46 -0400 Received: from foss.arm.com ([217.140.110.172]:50186 "EHLO foss.arm.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S232976AbhEZVoo (ORCPT ); Wed, 26 May 2021 17:44:44 -0400 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 69F2F6D; Wed, 26 May 2021 14:43:12 -0700 (PDT) Received: from e120325.cambridge.arm.com (usa-sjc-imap-foss1.foss.arm.com [10.121.207.14]) by usa-sjc-imap-foss1.foss.arm.com (Postfix) with ESMTPSA id CCA213F73B; Wed, 26 May 2021 14:43:10 -0700 (PDT) Date: Wed, 26 May 2021 22:43:08 +0100 From: Beata Michalska To: Dietmar Eggemann Cc: Valentin Schneider , linux-kernel@vger.kernel.org, peterz@infradead.org, mingo@redhat.com, juri.lelli@redhat.com, vincent.guittot@linaro.org, corbet@lwn.net, rdunlap@infradead.org, linux-doc@vger.kernel.org Subject: Re: [PATCH v5 2/3] sched/topology: Rework CPU capacity asymmetry detection Message-ID: <20210526214308.GB1712@e120325.cambridge.arm.com> References: <20210524101617.8965-1-beata.michalska@arm.com> <20210524101617.8965-3-beata.michalska@arm.com> <87fsyc6mfz.mognet@arm.com> <20210524225508.GA14880@e120325.cambridge.arm.com> <87a6oj6sxo.mognet@arm.com> <20210525102945.GA24210@e120325.cambridge.arm.com> <98ad8837-b9b8-ff50-5a91-8d5951ee757c@arm.com> <20210526121546.GA13262@e120325.cambridge.arm.com> <1cae4fcc-d276-f66d-c094-35571233d923@arm.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <1cae4fcc-d276-f66d-c094-35571233d923@arm.com> User-Agent: Mutt/1.9.4 (2018-02-28) Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Wed, May 26, 2021 at 08:17:25PM +0200, Dietmar Eggemann wrote: > On 26/05/2021 14:15, Beata Michalska wrote: > > On Wed, May 26, 2021 at 11:52:25AM +0200, Dietmar Eggemann wrote: > >> On 25/05/2021 12:29, Beata Michalska wrote: > >>> On Tue, May 25, 2021 at 10:53:07AM +0100, Valentin Schneider wrote: > >>>> On 24/05/21 23:55, Beata Michalska wrote: > >>>>> On Mon, May 24, 2021 at 07:01:04PM +0100, Valentin Schneider wrote: > >>>>>> On 24/05/21 11:16, Beata Michalska wrote: > > [...] > > >> static inline int > >> asym_cpu_capacity_classify(struct sched_domain *sd, > >> const struct cpumask *cpu_map) > >> { > >> int sd_span_match = 0, cpu_map_match = 0, flags = 0; > >> struct asym_cap_data *entry; > >> > >> list_for_each_entry(entry, &asym_cap_list, link) { > >> if (cpumask_intersects(sched_domain_span(sd), entry->cpu_mask)) > >> ++sd_span_match; > >> else if (cpumask_intersects(cpu_map, entry->cpu_mask)) > >> ++cpu_map_match; > >> } > >> > >> WARN_ON_ONCE(!sd_span_match); > >> > >> if (sd_span_match > 1) { > >> flags |= SD_ASYM_CPUCAPACITY; > >> if (!cpu_map_match) > >> flags |= SD_ASYM_CPUCAPACITY_FULL; > >> } > >> > >> return flags; > >> } > > So I planned to drop the list_is_singular check as it is needless really. > > Otherwise, I am not really convinced by the suggestion. I could add comments > > around current version to make it more ..... 'digestible' but I'd rather > > stay with it as it seems more compact to me (subjective). > > You could pass in `const struct cpumask *sd_span` instead of `struct > sched_domain *sd` though. To make it clear that both masks are used to > compare against the cpumasks of the asym_cap_list entries. > I could definitely do that, though if I switch to arrays for CPUs masks, it might get a bit confusing again. No strong preferences here though. Can do either or both. Thanks. --- BR B. > static inline int > -asym_cpu_capacity_classify(struct sched_domain *sd, > +asym_cpu_capacity_classify(const struct cpumask *sd_span, > const struct cpumask *cpu_map) > { > int sd_asym_flags = SD_ASYM_CPUCAPACITY | SD_ASYM_CPUCAPACITY_FULL; > @@ -1377,14 +1378,14 @@ asym_cpu_capacity_classify(struct sched_domain *sd, > goto leave; > > list_for_each_entry(entry, &asym_cap_list, link) { > - if (cpumask_intersects(sched_domain_span(sd), entry->cpu_mask)) { > + if (cpumask_intersects(sd_span, entry->cpu_mask)) { > ++asym_cap_count; > } else { > /* > * CPUs with given capacity might be offline > * so make sure this is not the case > */ > - if (cpumask_intersects(entry->cpu_mask, cpu_map)) { > + if (cpumask_intersects(cpu_map, entry->cpu_mask)) { > sd_asym_flags &= ~SD_ASYM_CPUCAPACITY_FULL; > if (asym_cap_count > 1) > break; > @@ -1395,7 +1396,6 @@ asym_cpu_capacity_classify(struct sched_domain *sd, > leave: > return asym_cap_count > 1 ? sd_asym_flags : 0; > } > -#endif > > static inline struct asym_cap_data * > asym_cpu_capacity_get_data(unsigned long capacity) > @@ -1589,6 +1589,7 @@ sd_init(struct sched_domain_topology_level *tl, > struct sd_data *sdd = &tl->data; > struct sched_domain *sd = *per_cpu_ptr(sdd->sd, cpu); > int sd_id, sd_weight, sd_flags = 0; > + struct cpumask *sd_span; > > #ifdef CONFIG_NUMA > /* > @@ -1636,10 +1637,11 @@ sd_init(struct sched_domain_topology_level *tl, > #endif > }; > > - cpumask_and(sched_domain_span(sd), cpu_map, tl->mask(cpu)); > - sd_id = cpumask_first(sched_domain_span(sd)); > + sd_span = sched_domain_span(sd); > + cpumask_and(sd_span, cpu_map, tl->mask(cpu)); > + sd_id = cpumask_first(sd_span); > > - sd->flags |= asym_cpu_capacity_classify(sd, cpu_map); > + sd->flags |= asym_cpu_capacity_classify(sd_span, cpu_map); > /* > * Convert topological properties into behaviour. > */