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=-15.8 required=3.0 tests=BAYES_00,DKIM_SIGNED, DKIM_VALID,DKIM_VALID_AU,HEADER_FROM_DIFFERENT_DOMAINS,INCLUDES_CR_TRAILER, INCLUDES_PATCH,MAILING_LIST_MULTI,SPF_HELO_NONE,SPF_PASS,URIBL_BLOCKED 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 D6387C64E8A for ; Mon, 30 Nov 2020 10:36:10 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 6286120825 for ; Mon, 30 Nov 2020 10:36:10 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=pass (2048-bit key) header.d=linaro.org header.i=@linaro.org header.b="EjYOkUfD" Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1728796AbgK3KgJ (ORCPT ); Mon, 30 Nov 2020 05:36:09 -0500 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:39242 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1725902AbgK3KgI (ORCPT ); Mon, 30 Nov 2020 05:36:08 -0500 Received: from mail-lf1-x143.google.com (mail-lf1-x143.google.com [IPv6:2a00:1450:4864:20::143]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 63D0CC0613D3 for ; Mon, 30 Nov 2020 02:35:28 -0800 (PST) Received: by mail-lf1-x143.google.com with SMTP id q13so19927777lfr.10 for ; Mon, 30 Nov 2020 02:35:28 -0800 (PST) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=linaro.org; s=google; h=mime-version:references:in-reply-to:from:date:message-id:subject:to :cc; bh=1efkswn4cUycQKBASwkUtMVwPaZz3RLBqwkA/yVPN2Y=; b=EjYOkUfDu7eW0Hd51AwmPtk74cTG0Ks5QPrXW6VSvqKwZGGbs8I80+8IfhoqxNOL3z RMAa25jUYC3mFzUkCq6m4KbVPvMyN63z70cVkEIxPunkyTeMA8vMxgPtb4J+INJf9+pE wx736R1hYMc+g2UumGJnFxPeCUQU7U3/+g/FNY4mRGQO3/F7GcAc0IBs43gsyU9X2GMd wU6ELTYYyULMmTrCc6+qyI7CM+4yXJJ+sfxysvEAG/Ch3uBS9WQOpRXb98iu+QjIz6yd 4E8Qj0+Ty5m1ePO9Akp1J3acjuDaWOMKUmzgM01xeIN9eKjkcjLNnBxNVd8XtaxieG0o wR8A== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20161025; h=x-gm-message-state:mime-version:references:in-reply-to:from:date :message-id:subject:to:cc; bh=1efkswn4cUycQKBASwkUtMVwPaZz3RLBqwkA/yVPN2Y=; b=k4nTSUrpIOE1TA5Wg1XP+jLYlz66pFrgPHzmMoDYJzdSeqDqQP0ozbNq3gyfn8V98+ DcdnOVJGICxZqyl1BGhI/ZdELB42cCFOG2Ug6Lft8WxstHdtjW4eDT60KUf+RMdmHI7F GEIn98oJjkeyS0m7rNfMRDqWyFCcFc6BL306u8KQ4UJo3YshsCtV16pjOin0SaFmeqvZ jN6x/ul6KbdjkomoDPO/tck5ZFfvQ9iOrKXuQR4tNeOEwcEOqCrlSqbf+jF+zvOE+vOe ITpSMUhxCWgk2uaQ/itautVKI5DUOdrx0j55AbssXZMZLmuZniEiV8RXyvl7TKcDLucY uEPw== X-Gm-Message-State: AOAM532CQIUhjLkn4axyGpXLC5fkSyVspYSWi+KzTCqry498NFXk7p/q MqiuI8EzYn620RlCGtshlo8Yy93Gnx52uG5T47du/A== X-Google-Smtp-Source: ABdhPJy/cDd7cSD+3NnLHGJtfwf72cutGWqAHZMYaXiKl6y4iCLcHSfnIFbnpKyq8BQTm+Glxw/0BT1fbSCt8a6lnKw= X-Received: by 2002:a19:8347:: with SMTP id f68mr9106032lfd.83.1606732526677; Mon, 30 Nov 2020 02:35:26 -0800 (PST) MIME-Version: 1.0 References: <20201117232003.3580179-1-joel@joelfernandes.org> <20201117232003.3580179-15-joel@joelfernandes.org> In-Reply-To: <20201117232003.3580179-15-joel@joelfernandes.org> From: Vincent Guittot Date: Mon, 30 Nov 2020 11:35:15 +0100 Message-ID: Subject: Re: [PATCH -tip 14/32] sched: migration changes for core scheduling To: "Joel Fernandes (Google)" Cc: Nishanth Aravamudan , Julien Desfossez , Peter Zijlstra , Tim Chen , Vineeth Pillai , Aaron Lu , Aubrey Li , Thomas Gleixner , linux-kernel , Ingo Molnar , Linus Torvalds , Frederic Weisbecker , Kees Cook , Greg Kerr , 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, Paul Turner , Steven Rostedt , Patrick Bellasi , Jiang Biao , Alexandre Chartre , James Bottomley , OWeisse@umich.edu, Dhaval Giani , Junaid Shahid , jsbarnes@google.com, "Hyser,Chris" , Ben Segall , Josh Don , Hao Luo , Tom Lendacky , Aubrey Li , Aubrey Li , "Paul E. McKenney" , Tim Chen Content-Type: text/plain; charset="UTF-8" Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Wed, 18 Nov 2020 at 00:20, Joel Fernandes (Google) wrote: > > From: Aubrey Li > > - Don't migrate if there is a cookie mismatch > Load balance tries to move task from busiest CPU to the > destination CPU. When core scheduling is enabled, if the > task's cookie does not match with the destination CPU's > core cookie, this task will be skipped by this CPU. This > mitigates the forced idle time on the destination CPU. > > - Select cookie matched idle CPU > In the fast path of task wakeup, select the first cookie matched > idle CPU instead of the first idle CPU. > > - Find cookie matched idlest CPU > In the slow path of task wakeup, find the idlest CPU whose core > cookie matches with task's cookie > > - Don't migrate task if cookie not match > For the NUMA load balance, don't migrate task to the CPU whose > core cookie does not match with task's cookie > > Tested-by: Julien Desfossez > Signed-off-by: Aubrey Li > Signed-off-by: Tim Chen > Signed-off-by: Vineeth Remanan Pillai > Signed-off-by: Joel Fernandes (Google) > --- > kernel/sched/fair.c | 64 ++++++++++++++++++++++++++++++++++++++++---- > kernel/sched/sched.h | 29 ++++++++++++++++++++ > 2 files changed, 88 insertions(+), 5 deletions(-) > > diff --git a/kernel/sched/fair.c b/kernel/sched/fair.c > index de82f88ba98c..ceb3906c9a8a 100644 > --- a/kernel/sched/fair.c > +++ b/kernel/sched/fair.c > @@ -1921,6 +1921,15 @@ static void task_numa_find_cpu(struct task_numa_env *env, > if (!cpumask_test_cpu(cpu, env->p->cpus_ptr)) > continue; > > +#ifdef CONFIG_SCHED_CORE > + /* > + * 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; > +#endif > + > env->dst_cpu = cpu; > if (task_numa_compare(env, taskimp, groupimp, maymove)) > break; > @@ -5867,11 +5876,17 @@ 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); > + > +#ifdef CONFIG_SCHED_CORE > + if (!sched_core_cookie_match(rq, p)) > + continue; > +#endif > + > 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) { > /* > @@ -6129,8 +6144,18 @@ 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)) > - break; > + > + if (available_idle_cpu(cpu) || sched_idle_cpu(cpu)) { > +#ifdef CONFIG_SCHED_CORE > + /* > + * If Core Scheduling is enabled, select this cpu > + * only if the process cookie matches core cookie. > + */ > + if (sched_core_enabled(cpu_rq(cpu)) && > + p->core_cookie == cpu_rq(cpu)->core->core_cookie) > +#endif > + break; > + } This makes code unreadable. Put this coresched specific stuff in an inline function; You can have a look at what is done with asym_fits_capacity() > } > > time = cpu_clock(this) - time; > @@ -7530,8 +7555,9 @@ int can_migrate_task(struct task_struct *p, struct lb_env *env) > * We do not migrate tasks that are: > * 1) throttled_lb_pair, or > * 2) cannot be migrated to this CPU due to cpus_ptr, or > - * 3) running (obviously), or > - * 4) are cache-hot on their current CPU. > + * 3) task's cookie does not match with this CPU's core cookie > + * 4) running (obviously), or > + * 5) are cache-hot on their current CPU. > */ > if (throttled_lb_pair(task_group(p), env->src_cpu, env->dst_cpu)) > return 0; > @@ -7566,6 +7592,15 @@ int can_migrate_task(struct task_struct *p, struct lb_env *env) > return 0; > } > > +#ifdef CONFIG_SCHED_CORE > + /* > + * 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 0; > +#endif > + > /* Record that we found atleast one task that could run on dst_cpu */ > env->flags &= ~LBF_ALL_PINNED; > > @@ -8792,6 +8827,25 @@ find_idlest_group(struct sched_domain *sd, struct task_struct *p, int this_cpu) > p->cpus_ptr)) > continue; > > +#ifdef CONFIG_SCHED_CORE > + if (sched_core_enabled(cpu_rq(this_cpu))) { > + int i = 0; > + bool cookie_match = false; > + > + for_each_cpu(i, sched_group_span(group)) { > + struct rq *rq = cpu_rq(i); > + > + if (sched_core_cookie_match(rq, p)) { > + cookie_match = true; > + break; > + } > + } > + /* Skip over this group if no cookie matched */ > + if (!cookie_match) > + continue; > + } > +#endif same here, encapsulate this to keep find_idlest_group readable > + > local_group = cpumask_test_cpu(this_cpu, > sched_group_span(group)); > > diff --git a/kernel/sched/sched.h b/kernel/sched/sched.h > index e72942a9ee11..de553d39aa40 100644 > --- a/kernel/sched/sched.h > +++ b/kernel/sched/sched.h > @@ -1135,6 +1135,35 @@ static inline raw_spinlock_t *rq_lockp(struct rq *rq) > > bool cfs_prio_less(struct task_struct *a, struct task_struct *b); > > +/* > + * Helper 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_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; > +} > + > extern void queue_core_balance(struct rq *rq); > > #else /* !CONFIG_SCHED_CORE */ > -- > 2.29.2.299.gdc1121823c-goog >