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=-6.9 required=3.0 tests=BAYES_00, CHARSET_FARAWAY_HEADER,DKIM_SIGNED,DKIM_VALID,DKIM_VALID_AU, HEADER_FROM_DIFFERENT_DOMAINS,INCLUDES_PATCH,MAILING_LIST_MULTI,SIGNED_OFF_BY, SPF_HELO_NONE,SPF_PASS 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 6FE4EC433DF for ; Wed, 22 Jul 2020 08:54:42 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 18391207BB for ; Wed, 22 Jul 2020 08:54:42 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=pass (1024-bit key) header.d=tencent.com header.i=@tencent.com header.b="hFGEKLml" Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1730997AbgGVIyl (ORCPT ); Wed, 22 Jul 2020 04:54:41 -0400 Received: from mail4.tencent.com ([183.57.53.109]:57111 "EHLO mail4.tencent.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1726807AbgGVIyk (ORCPT ); Wed, 22 Jul 2020 04:54:40 -0400 Received: from EX-SZ020.tencent.com (unknown [10.28.6.40]) by mail4.tencent.com (Postfix) with ESMTP id 8AB23724CA; Wed, 22 Jul 2020 16:54:35 +0800 (CST) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=tencent.com; s=s202002; t=1595408075; bh=Z5wz6SguzXs1PozL8x1L5jrEg9NHhzbRHa0IkJjnaBY=; h=From:To:CC:Subject:Date:References:In-Reply-To; b=hFGEKLmlK0S2lV9JNHwkCOo+n/b6i+VTqhyOu6xHFsZTX3tjVe6cLNLdYko/5ZG2l Co+DaHTbfH0yXOyTyT7zpLQJ++gl+24LFOkwIA6XjX46xGWFcB9qd/4MTckyobmURP bvbG5AawRtsRFKhCaVxTTAOOmbT9lpqiRN0ELlYE= Received: from EX-SZ003.tencent.com (10.28.6.15) by EX-SZ020.tencent.com (10.28.6.40) with Microsoft SMTP Server (version=TLS1_2, cipher=TLS_ECDHE_RSA_WITH_AES_128_GCM_SHA256) id 15.1.1847.3; Wed, 22 Jul 2020 16:54:35 +0800 Received: from EX-SZ012.tencent.com (10.28.6.36) by EX-SZ003.tencent.com (10.28.6.15) with Microsoft SMTP Server (version=TLS1_2, cipher=TLS_ECDHE_RSA_WITH_AES_128_GCM_SHA256) id 15.1.1847.3; Wed, 22 Jul 2020 16:54:34 +0800 Received: from EX-SZ012.tencent.com ([fe80::f57b:8971:e6d4:fe6b]) by EX-SZ012.tencent.com ([fe80::f57b:8971:e6d4:fe6b%3]) with mapi id 15.01.1847.007; Wed, 22 Jul 2020 16:54:31 +0800 From: =?iso-2022-jp?B?YmVuYmppYW5nKBskQj5VSTcbKEIp?= To: Vineeth Remanan Pillai , "Li, Aubrey" CC: Nishanth Aravamudan , Julien Desfossez , Peter Zijlstra , "Tim Chen" , "mingo@kernel.org" , "tglx@linutronix.de" , "pjt@google.com" , "torvalds@linux-foundation.org" , Aubrey Li , "linux-kernel@vger.kernel.org" , "subhra.mazumdar@oracle.com" , "fweisbec@gmail.com" , "keescook@chromium.org" , "kerrnel@google.com" , Phil Auld , Aaron Lu , Aubrey Li , Valentin Schneider , Mel Gorman , Pawan Gupta , Paolo Bonzini , Joel Fernandes , "joel@joelfernandes.org" , "vineethrp@gmail.com" , Chen Yu , Christian Brauner , Aubrey Li Subject: Re: [RFC PATCH 11/16] sched: migration changes for core scheduling(Internet mail) Thread-Topic: [RFC PATCH 11/16] sched: migration changes for core scheduling(Internet mail) Thread-Index: AQHWTzVqBGu6Ndoz306mL65QHjIl9akS5uOA Date: Wed, 22 Jul 2020 08:54:31 +0000 Message-ID: <72869477-AA03-47D4-96C5-D3CDBDBC12E7@tencent.com> References: <9044a2ebde089483d45c091752d208a878c604ac.1593530334.git.vpillai@digitalocean.com> In-Reply-To: <9044a2ebde089483d45c091752d208a878c604ac.1593530334.git.vpillai@digitalocean.com> Accept-Language: zh-CN, en-US Content-Language: en-US X-MS-Has-Attach: X-MS-TNEF-Correlator: x-originating-ip: [9.45.201.110] Content-Type: text/plain; charset="iso-2022-jp" Content-ID: <8204BD307F8510479E149D9AF19645B7@tencent.com> Content-Transfer-Encoding: quoted-printable MIME-Version: 1.0 Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Hi, Aubrey, > On Jul 1, 2020, at 5:32 AM, Vineeth Remanan Pillai wrote: >=20 > From: Aubrey Li >=20 > - 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. >=20 > - 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. >=20 > - Find cookie matched idlest CPU > In the slow path of task wakeup, find the idlest CPU whose core > cookie matches with task's cookie >=20 > - 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 >=20 > Signed-off-by: Aubrey Li > Signed-off-by: Tim Chen > Signed-off-by: Vineeth Remanan Pillai > --- > kernel/sched/fair.c | 64 ++++++++++++++++++++++++++++++++++++++++---- > kernel/sched/sched.h | 29 ++++++++++++++++++++ > 2 files changed, 88 insertions(+), 5 deletions(-) >=20 > diff --git a/kernel/sched/fair.c b/kernel/sched/fair.c > index d16939766361..33dc4bf01817 100644 > --- a/kernel/sched/fair.c > +++ b/kernel/sched/fair.c > @@ -2051,6 +2051,15 @@ static void task_numa_find_cpu(struct task_numa_en= v *env, > if (!cpumask_test_cpu(cpu, env->p->cpus_ptr)) > continue; >=20 > +#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 =3D cpu; > if (task_numa_compare(env, taskimp, groupimp, maymove)) > break; > @@ -5963,11 +5972,17 @@ find_idlest_group_cpu(struct sched_group *group, = struct task_struct *p, int this >=20 > /* Traverse only the allowed CPUs */ > for_each_cpu_and(i, sched_group_span(group), p->cpus_ptr) { > + struct rq *rq =3D cpu_rq(i); > + > +#ifdef CONFIG_SCHED_CORE > + if (!sched_core_cookie_match(rq, p)) > + continue; > +#endif > + > if (sched_idle_cpu(i)) > return i; >=20 > if (available_idle_cpu(i)) { > - struct rq *rq =3D cpu_rq(i); > struct cpuidle_state *idle =3D idle_get_state(rq); > if (idle && idle->exit_latency < min_exit_latency) { > /* > @@ -6224,8 +6239,18 @@ 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 =3D=3D cpu_rq(cpu)->core->core_cookie) Why not also add similar logic in select_idle_smt to reduce forced-idle? :) > +#endif > + break; > + } > } >=20 > time =3D cpu_clock(this) - time; > @@ -7609,8 +7634,9 @@ 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; > @@ -7645,6 +7671,15 @@ int can_migrate_task(struct task_struct *p, struct= lb_env *env) > return 0; > } >=20 > +#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 &=3D ~LBF_ALL_PINNED; >=20 > @@ -8857,6 +8892,25 @@ find_idlest_group(struct sched_domain *sd, struct = task_struct *p, > p->cpus_ptr)) > continue; >=20 > +#ifdef CONFIG_SCHED_CORE > + if (sched_core_enabled(cpu_rq(this_cpu))) { > + int i =3D 0; > + bool cookie_match =3D false; > + > + for_each_cpu(i, sched_group_span(group)) { Should we consider the p->cpus_ptr here? like, for_each_cpu_and(i, sched_group_span(group), p->cpus_ptr ) { ... } Thx. Regards, Jiang > + struct rq *rq =3D cpu_rq(i); > + > + if (sched_core_cookie_match(rq, p)) { > + cookie_match =3D true; > + break; > + } > + } > + /* Skip over this group if no cookie matched */ > + if (!cookie_match) > + continue; > + } > +#endif > + > local_group =3D cpumask_test_cpu(this_cpu, > sched_group_span(group)); >=20 > diff --git a/kernel/sched/sched.h b/kernel/sched/sched.h > index 464559676fd2..875796d43fca 100644 > --- a/kernel/sched/sched.h > +++ b/kernel/sched/sched.h > @@ -1089,6 +1089,35 @@ static inline raw_spinlock_t *rq_lockp(struct rq *= rq) > bool cfs_prio_less(struct task_struct *a, struct task_struct *b); > void sched_core_adjust_sibling_vruntime(int cpu, bool coresched_enabled); >=20 > +/* > + * Helper to check if the CPU's core cookie matches with the task's cook= ie > + * when core scheduling is enabled. > + * A special case is that the task's cookie always matches with CPU's co= re > + * cookie if the CPU is in an idle core. > + */ > +static inline bool sched_core_cookie_match(struct rq *rq, struct task_st= ruct *p) > +{ > + bool idle_core =3D 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 =3D false; > + break; > + } > + } > + > + /* > + * A CPU in an idle core is always the best choice for tasks with > + * cookies. > + */ > + return idle_core || rq->core->core_cookie =3D=3D p->core_cookie; > +} > + > extern void queue_core_balance(struct rq *rq); >=20 > #else /* !CONFIG_SCHED_CORE */ > --=20 > 2.17.1 >=20 >=20