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[23.128.96.18]) by mx.google.com with ESMTP id hr14si11085113ejc.396.2020.11.30.04.38.17; Mon, 30 Nov 2020 04:38:41 -0800 (PST) Received-SPF: pass (google.com: domain of linux-kernel-owner@vger.kernel.org designates 23.128.96.18 as permitted sender) client-ip=23.128.96.18; Authentication-Results: mx.google.com; spf=pass (google.com: domain of linux-kernel-owner@vger.kernel.org designates 23.128.96.18 as permitted sender) smtp.mailfrom=linux-kernel-owner@vger.kernel.org; dmarc=fail (p=NONE sp=NONE dis=NONE) header.from=intel.com Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1725908AbgK3Meo (ORCPT + 99 others); Mon, 30 Nov 2020 07:34:44 -0500 Received: from mga18.intel.com ([134.134.136.126]:36122 "EHLO mga18.intel.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1725849AbgK3Meo (ORCPT ); Mon, 30 Nov 2020 07:34:44 -0500 IronPort-SDR: pAlejKfalyYeDPaB4oUsdRaEI/C/IKpiMomw8J7xZOSu08HeTxIc0JAEDuwfpFLaMHvigQnEC3 qCAlOpj69h3A== X-IronPort-AV: E=McAfee;i="6000,8403,9820"; a="160398080" X-IronPort-AV: E=Sophos;i="5.78,381,1599548400"; d="scan'208";a="160398080" X-Amp-Result: SKIPPED(no attachment in message) X-Amp-File-Uploaded: False Received: from fmsmga003.fm.intel.com ([10.253.24.29]) by orsmga106.jf.intel.com with ESMTP/TLS/ECDHE-RSA-AES256-GCM-SHA384; 30 Nov 2020 04:33:02 -0800 IronPort-SDR: IbPsYnqSwtnb1o4+GLCJeXVnmngfyHvQ2KmVNDszlWuHSAuiPXk8XAjdpopgvWKAs5e943hhml M24DgKd9V3Pw== X-ExtLoop1: 1 X-IronPort-AV: E=Sophos;i="5.78,381,1599548400"; d="scan'208";a="372478051" Received: from cli6-desk1.ccr.corp.intel.com (HELO [10.239.161.125]) ([10.239.161.125]) by FMSMGA003.fm.intel.com with ESMTP; 30 Nov 2020 04:32:51 -0800 Subject: Re: [PATCH -tip 14/32] sched: migration changes for core scheduling To: Vincent Guittot , "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 , "Paul E. McKenney" , Tim Chen References: <20201117232003.3580179-1-joel@joelfernandes.org> <20201117232003.3580179-15-joel@joelfernandes.org> From: "Li, Aubrey" Message-ID: <412d1b62-d2ef-ce01-7739-0e8f2a98e233@linux.intel.com> Date: Mon, 30 Nov 2020 20:32:50 +0800 User-Agent: Mozilla/5.0 (Windows NT 10.0; WOW64; rv:68.0) Gecko/20100101 Thunderbird/68.9.0 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 2020/11/30 18:35, Vincent Guittot wrote: > 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() > This is done in a refined version. Sorry I pasted the version embedded in this thread, this is not the latest version. >> } >> >> 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 > Okay, I'll try to refine this. Thanks, -Aubrey