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,NICE_REPLY_A, SPF_HELO_NONE,SPF_PASS,USER_AGENT_SANE_1 autolearn=ham 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 AC965C433F7 for ; Mon, 22 Mar 2021 12:33:08 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 8B9F561990 for ; Mon, 22 Mar 2021 12:33:08 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S231535AbhCVMdD (ORCPT ); Mon, 22 Mar 2021 08:33:03 -0400 Received: from mga06.intel.com ([134.134.136.31]:35411 "EHLO mga06.intel.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S231330AbhCVMbX (ORCPT ); Mon, 22 Mar 2021 08:31:23 -0400 IronPort-SDR: eEHvhf+z+pBSl9aHCTzFrN3rGiT0LEwdnWXWwRRqXne3AcBwDrFpo+JbKVlyl+TQXUIm07TPGf OgRFuf3GDH1A== X-IronPort-AV: E=McAfee;i="6000,8403,9930"; a="251614209" X-IronPort-AV: E=Sophos;i="5.81,268,1610438400"; d="scan'208";a="251614209" Received: from fmsmga002.fm.intel.com ([10.253.24.26]) by orsmga104.jf.intel.com with ESMTP/TLS/ECDHE-RSA-AES256-GCM-SHA384; 22 Mar 2021 05:31:22 -0700 IronPort-SDR: Qv4JQEGlPZDWQbLq4Ay9nrE+LAUxXHs9tp3Se0K+syJvN9j00Lu5WOUpa+WFdowTWddFzYiaUi VLu5LNvENwRQ== X-ExtLoop1: 1 X-IronPort-AV: E=Sophos;i="5.81,268,1610438400"; d="scan'208";a="441152125" Received: from cli6-desk1.ccr.corp.intel.com (HELO [10.239.161.125]) ([10.239.161.125]) by fmsmga002.fm.intel.com with ESMTP; 22 Mar 2021 05:31:10 -0700 Subject: Re: [PATCH 1/6] sched: migration changes for core scheduling To: Peter Zijlstra Cc: "Joel Fernandes (Google)" , Nishanth Aravamudan , Julien Desfossez , Tim Chen , Vineeth Pillai , Aaron Lu , Aubrey Li , tglx@linutronix.de, linux-kernel@vger.kernel.org, mingo@kernel.org, torvalds@linux-foundation.org, fweisbec@gmail.com, keescook@chromium.org, Phil Auld , Valentin Schneider , Mel Gorman , Pawan Gupta , Paolo Bonzini , vineeth@bitbyteword.org, Chen Yu , Christian Brauner , Agata Gruza , Antonio Gomez Iglesias , graf@amazon.com, konrad.wilk@oracle.com, dfaggioli@suse.com, rostedt@goodmis.org, benbjiang@tencent.com, Alexandre Chartre , James.Bottomley@hansenpartnership.com, OWeisse@umich.edu, Dhaval Giani , chris.hyser@oracle.com, Josh Don , Hao Luo , Tom Lendacky , Aubrey Li References: <20210319203253.3352417-1-joel@joelfernandes.org> <20210319203253.3352417-2-joel@joelfernandes.org> <20210320153457.GX4746@worktop.programming.kicks-ass.net> <28e13609-c526-c6ee-22a3-898652aed5e6@linux.intel.com> From: "Li, Aubrey" Message-ID: Date: Mon, 22 Mar 2021 20:31:09 +0800 User-Agent: Mozilla/5.0 (Windows NT 10.0; Win64; x64; rv:78.0) Gecko/20100101 Thunderbird/78.7.1 MIME-Version: 1.0 In-Reply-To: Content-Type: text/plain; charset=utf-8 Content-Language: en-US Content-Transfer-Encoding: 7bit Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On 2021/3/22 16:57, Peter Zijlstra wrote: > >> Do you have any suggestions before we drop it? > > Yeah, how about you make it part of task_hot() ? Have task_hot() refuse > migration it the cookie doesn't match. > > task_hot() is a hint and will get ignored when appropriate. > Please let me know if I put cookie match check at the right position in task_hot(), if so, I'll obtain some performance data of it. Thanks, -Aubrey ======================================================= diff --git a/kernel/sched/fair.c b/kernel/sched/fair.c index 7f2fb08..d4bdcf9 100644 --- a/kernel/sched/fair.c +++ b/kernel/sched/fair.c @@ -1912,6 +1912,13 @@ static void task_numa_find_cpu(struct task_numa_env *env, if (!cpumask_test_cpu(cpu, env->p->cpus_ptr)) continue; + /* + * Skip this cpu if source task's cookie does not match + * with CPU's core cookie. + */ + if (!sched_core_cookie_match(cpu_rq(cpu), env->p)) + continue; + env->dst_cpu = cpu; if (task_numa_compare(env, taskimp, groupimp, maymove)) break; @@ -5847,11 +5854,15 @@ find_idlest_group_cpu(struct sched_group *group, struct task_struct *p, int this /* Traverse only the allowed CPUs */ for_each_cpu_and(i, sched_group_span(group), p->cpus_ptr) { + struct rq *rq = cpu_rq(i); + + if (!sched_core_cookie_match(rq, p)) + continue; + if (sched_idle_cpu(i)) return i; if (available_idle_cpu(i)) { - struct rq *rq = cpu_rq(i); struct cpuidle_state *idle = idle_get_state(rq); if (idle && idle->exit_latency < min_exit_latency) { /* @@ -6109,7 +6120,9 @@ static int select_idle_cpu(struct task_struct *p, struct sched_domain *sd, int t for_each_cpu_wrap(cpu, cpus, target) { if (!--nr) return -1; - if (available_idle_cpu(cpu) || sched_idle_cpu(cpu)) + + if ((available_idle_cpu(cpu) || sched_idle_cpu(cpu)) && + sched_cpu_cookie_match(cpu_rq(cpu), p)) break; } @@ -7427,6 +7440,14 @@ static int task_hot(struct task_struct *p, struct lb_env *env) if (sysctl_sched_migration_cost == -1) return 1; + + /* + * Don't migrate task if the task's cookie does not match + * with the destination CPU's core cookie. + */ + if (!sched_core_cookie_match(cpu_rq(env->dst_cpu), p)) + return 1; + if (sysctl_sched_migration_cost == 0) return 0; @@ -8771,6 +8792,10 @@ find_idlest_group(struct sched_domain *sd, struct task_struct *p, int this_cpu) p->cpus_ptr)) continue; + /* Skip over this group if no cookie matched */ + if (!sched_group_cookie_match(cpu_rq(this_cpu), p, group)) + continue; + local_group = cpumask_test_cpu(this_cpu, sched_group_span(group)); diff --git a/kernel/sched/sched.h b/kernel/sched/sched.h index f094435..13254ea 100644 --- a/kernel/sched/sched.h +++ b/kernel/sched/sched.h @@ -1093,6 +1093,7 @@ static inline int cpu_of(struct rq *rq) #ifdef CONFIG_SCHED_CORE DECLARE_STATIC_KEY_FALSE(__sched_core_enabled); +static inline struct cpumask *sched_group_span(struct sched_group *sg); static inline bool sched_core_enabled(struct rq *rq) { @@ -1109,6 +1110,61 @@ static inline raw_spinlock_t *rq_lockp(struct rq *rq) bool cfs_prio_less(struct task_struct *a, struct task_struct *b, bool fi); +/* + * Helpers to check if the CPU's core cookie matches with the task's cookie + * when core scheduling is enabled. + * A special case is that the task's cookie always matches with CPU's core + * cookie if the CPU is in an idle core. + */ +static inline bool sched_cpu_cookie_match(struct rq *rq, struct task_struct *p) +{ + /* Ignore cookie match if core scheduler is not enabled on the CPU. */ + if (!sched_core_enabled(rq)) + return true; + + return rq->core->core_cookie == p->core_cookie; +} + +static inline bool sched_core_cookie_match(struct rq *rq, struct task_struct *p) +{ + bool idle_core = true; + int cpu; + + /* Ignore cookie match if core scheduler is not enabled on the CPU. */ + if (!sched_core_enabled(rq)) + return true; + + for_each_cpu(cpu, cpu_smt_mask(cpu_of(rq))) { + if (!available_idle_cpu(cpu)) { + idle_core = false; + break; + } + } + + /* + * A CPU in an idle core is always the best choice for tasks with + * cookies. + */ + return idle_core || rq->core->core_cookie == p->core_cookie; +} + +static inline bool sched_group_cookie_match(struct rq *rq, + struct task_struct *p, + struct sched_group *group) +{ + int cpu; + + /* Ignore cookie match if core scheduler is not enabled on the CPU. */ + if (!sched_core_enabled(rq)) + return true; + + for_each_cpu_and(cpu, sched_group_span(group), p->cpus_ptr) { + if (sched_core_cookie_match(rq, p)) + return true; + } + return false; +} + extern void queue_core_balance(struct rq *rq); bool cfs_prio_less(struct task_struct *a, struct task_struct *b, bool fi); @@ -1129,6 +1185,22 @@ static inline void queue_core_balance(struct rq *rq) { } +static inline bool sched_cpu_cookie_match(struct rq *rq, struct task_struct *p) +{ + return true; +} + +static inline bool sched_core_cookie_match(struct rq *rq, struct task_struct *p) +{ + return true; +} + +static inline bool sched_group_cookie_match(struct rq *rq, + struct task_struct *p, + struct sched_group *group) +{ + return true; +} #endif /* CONFIG_SCHED_CORE */ #ifdef CONFIG_SCHED_SMT