From patchwork Thu Jun 30 06:55:27 2022 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Yicong Yang X-Patchwork-Id: 12901271 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org Received: from bombadil.infradead.org (bombadil.infradead.org [198.137.202.133]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by smtp.lore.kernel.org (Postfix) with ESMTPS id 53F8DC433EF for ; Thu, 30 Jun 2022 06:58:10 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; q=dns/txt; c=relaxed/relaxed; d=lists.infradead.org; s=bombadil.20210309; h=Sender: Content-Transfer-Encoding:Content-Type:List-Subscribe:List-Help:List-Post: List-Archive:List-Unsubscribe:List-Id:MIME-Version:References:In-Reply-To: Message-ID:Date:Subject:CC:To:From:Reply-To:Content-ID:Content-Description: Resent-Date:Resent-From:Resent-Sender:Resent-To:Resent-Cc:Resent-Message-ID: List-Owner; bh=4gLDWFYKloDa7q5LLeFtNHjcDWXc5U67pX4r2YYDVtM=; b=tegk+pbh1uH/C1 2tDAkxnxdQfoDWkcRM9bZ7418zg+/FfwnZjOeM2QAFvVJYhpIrcppV05+/4eIBuOGwWMHsWLUlffx dZSnImW4AtobYB1NM7pPlCOF3dIMlA+Ou++BX/I6I/Krcr0eAGPsfeSHiR84tg+9DyxwaJtsuK4G3 4+9uReyQGyEIYVjydnEuHB/cZSncDuUlW+t7r/thpYSXJMawcb/DAqX7QTgrflnl9ydZtVmCT1Pvr HNzcVFqjhkkcK8CkE82IDiytWe78fIffyRA9XdDeqeZ90ShxeJaXn9fE/qWI/L9VXG2UpOsx3jgvg ywlU/2IZrYgLtDeP+GOw==; Received: from localhost ([::1] helo=bombadil.infradead.org) by bombadil.infradead.org with esmtp (Exim 4.94.2 #2 (Red Hat Linux)) id 1o6o6t-00FdBW-Fu; Thu, 30 Jun 2022 06:57:07 +0000 Received: from szxga02-in.huawei.com ([45.249.212.188]) by bombadil.infradead.org with esmtps (Exim 4.94.2 #2 (Red Hat Linux)) id 1o6o6n-00Fd3b-Vq for linux-arm-kernel@lists.infradead.org; Thu, 30 Jun 2022 06:57:04 +0000 Received: from canpemm500009.china.huawei.com (unknown [172.30.72.55]) by szxga02-in.huawei.com (SkyGuard) with ESMTP id 4LYTYq2ZzYzTgKs; Thu, 30 Jun 2022 14:53:19 +0800 (CST) Received: from localhost.localdomain (10.67.164.66) by canpemm500009.china.huawei.com (7.192.105.203) with Microsoft SMTP Server (version=TLS1_2, cipher=TLS_ECDHE_RSA_WITH_AES_128_GCM_SHA256) id 15.1.2375.24; Thu, 30 Jun 2022 14:56:49 +0800 From: Yicong Yang To: , , , , , , , CC: , , , , , , , , , , <21cnbao@gmail.com>, , , , , , , Subject: [PATCH v5 2/2] sched/fair: Scan cluster before scanning LLC in wake-up path Date: Thu, 30 Jun 2022 14:55:27 +0800 Message-ID: <20220630065527.38544-3-yangyicong@hisilicon.com> X-Mailer: git-send-email 2.31.0 In-Reply-To: <20220630065527.38544-1-yangyicong@hisilicon.com> References: <20220630065527.38544-1-yangyicong@hisilicon.com> MIME-Version: 1.0 X-Originating-IP: [10.67.164.66] X-ClientProxiedBy: dggems706-chm.china.huawei.com (10.3.19.183) To canpemm500009.china.huawei.com (7.192.105.203) X-CFilter-Loop: Reflected X-CRM114-Version: 20100106-BlameMichelson ( TRE 0.8.0 (BSD) ) MR-646709E3 X-CRM114-CacheID: sfid-20220629_235702_437609_7A49971E X-CRM114-Status: GOOD ( 15.29 ) X-BeenThere: linux-arm-kernel@lists.infradead.org X-Mailman-Version: 2.1.34 Precedence: list List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Sender: "linux-arm-kernel" Errors-To: linux-arm-kernel-bounces+linux-arm-kernel=archiver.kernel.org@lists.infradead.org From: Barry Song For platforms having clusters like Kunpeng920, CPUs within the same cluster have lower latency when synchronizing and accessing shared resources like cache. Thus, this patch tries to find an idle cpu within the cluster of the target CPU before scanning the whole LLC to gain lower latency. Note neither Kunpeng920 nor x86 Jacobsville supports SMT, so this patch doesn't consider SMT for this moment. Testing has been done on Kunpeng920 by pinning tasks to one numa and two numa. On Kunpeng920, Each numa has 8 clusters and each cluster has 4 CPUs. With this patch, We noticed enhancement on tbench within one numa or cross two numa. On numa 0: tip/core patched Hmean 1 345.89 ( 0.00%) 393.96 * 13.90%* Hmean 2 697.77 ( 0.00%) 786.04 * 12.65%* Hmean 4 1392.51 ( 0.00%) 1570.26 * 12.76%* Hmean 8 2800.61 ( 0.00%) 3083.98 * 10.12%* Hmean 16 5514.27 ( 0.00%) 6116.00 * 10.91%* Hmean 32 10869.81 ( 0.00%) 10782.98 * -0.80%* Hmean 64 8315.22 ( 0.00%) 8519.84 * 2.46%* Hmean 128 6324.47 ( 0.00%) 7159.35 * 13.20%* On numa 0-1: tip/core patched Hmean 1 348.68 ( 0.00%) 387.91 * 11.25%* Hmean 2 693.57 ( 0.00%) 774.91 * 11.73%* Hmean 4 1369.26 ( 0.00%) 1475.48 * 7.76%* Hmean 8 2772.99 ( 0.00%) 2984.61 * 7.63%* Hmean 16 4825.83 ( 0.00%) 5873.13 * 21.70%* Hmean 32 10250.32 ( 0.00%) 11688.06 * 14.03%* Hmean 64 16309.51 ( 0.00%) 19889.48 * 21.95%* Hmean 128 13022.32 ( 0.00%) 16005.64 * 22.91%* Hmean 256 11335.79 ( 0.00%) 13821.74 * 21.93%* Tested-by: Yicong Yang Signed-off-by: Barry Song Signed-off-by: Yicong Yang Reviewed-by: Tim Chen --- kernel/sched/fair.c | 44 +++++++++++++++++++++++++++++++++++++++++--- 1 file changed, 41 insertions(+), 3 deletions(-) diff --git a/kernel/sched/fair.c b/kernel/sched/fair.c index f80ae86bb404..dff5dec0d792 100644 --- a/kernel/sched/fair.c +++ b/kernel/sched/fair.c @@ -6323,6 +6323,40 @@ static inline int select_idle_smt(struct task_struct *p, struct sched_domain *sd #endif /* CONFIG_SCHED_SMT */ +#ifdef CONFIG_SCHED_CLUSTER +/* + * Scan the cluster domain for idle CPUs and clear cluster cpumask after scanning + */ +static inline int scan_cluster(struct task_struct *p, struct cpumask *cpus, + int target, int *nr) +{ + struct sched_domain *sd = rcu_dereference(per_cpu(sd_cluster, target)); + int cpu, idle_cpu; + + /* TODO: Support SMT system with cluster topology */ + if (!sched_smt_active() && sd) { + for_each_cpu_and(cpu, cpus, sched_domain_span(sd)) { + if (!--*nr) + return -1; + + idle_cpu = __select_idle_cpu(cpu, p); + if ((unsigned int)idle_cpu < nr_cpumask_bits) + return idle_cpu; + } + + cpumask_andnot(cpus, cpus, sched_domain_span(sd)); + } + + return -1; +} +#else +static inline int scan_cluster(struct task_struct *p, struct cpumask *cpus, + int target, int *nr) +{ + return -1; +} +#endif + /* * Scan the LLC domain for idle CPUs; this is dynamically regulated by * comparing the average scan cost (tracked in sd->avg_scan_cost) against the @@ -6383,6 +6417,10 @@ static int select_idle_cpu(struct task_struct *p, struct sched_domain *sd, bool } } + idle_cpu = scan_cluster(p, cpus, target, &nr); + if ((unsigned int)idle_cpu < nr_cpumask_bits) + return idle_cpu; + for_each_cpu_wrap(cpu, cpus, target + 1) { if (has_idle_core) { i = select_idle_core(p, cpu, cpus, &idle_cpu); @@ -6390,7 +6428,7 @@ static int select_idle_cpu(struct task_struct *p, struct sched_domain *sd, bool return i; } else { - if (!--nr) + if (--nr <= 0) return -1; idle_cpu = __select_idle_cpu(cpu, p); if ((unsigned int)idle_cpu < nr_cpumask_bits) @@ -6489,7 +6527,7 @@ static int select_idle_sibling(struct task_struct *p, int prev, int target) /* * If the previous CPU is cache affine and idle, don't be stupid: */ - if (prev != target && cpus_share_cache(prev, target) && + if (prev != target && cpus_share_lowest_cache(prev, target) && (available_idle_cpu(prev) || sched_idle_cpu(prev)) && asym_fits_capacity(task_util, prev)) return prev; @@ -6515,7 +6553,7 @@ static int select_idle_sibling(struct task_struct *p, int prev, int target) p->recent_used_cpu = prev; if (recent_used_cpu != prev && recent_used_cpu != target && - cpus_share_cache(recent_used_cpu, target) && + cpus_share_lowest_cache(recent_used_cpu, target) && (available_idle_cpu(recent_used_cpu) || sched_idle_cpu(recent_used_cpu)) && cpumask_test_cpu(p->recent_used_cpu, p->cpus_ptr) && asym_fits_capacity(task_util, recent_used_cpu)) {