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 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 AA544C43334 for ; Thu, 9 Jun 2022 12:18:06 +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=dcJgI0dvynaP7UI3MdYWcJjdkTbMrJw1fyA2ohkegc0=; b=1IkTbGevA3PHWt nafx5dp3xHbV5YXGexySSvRBwGOqaAAMymSj4yeplqB2pzt9Pe/91uWulj0IUH/Jy8WFNzD3xwc3V Yl1wZS/vkbXfQ2LQMsjZnark4JPEtfi8DzeIG0p2LIm//ZisRFY8hUJPB0xJov8xwb9XsdFyawBd8 bF57JoE3OoPVVc4UbUPE+GWmzuCxd/ldwwdWQSJpN7qHPSeEDsZuAyybU/p8maajpbbXD0rsjcMOz L+l2YyjR3WiQH6foMF0T3f3KR30DTmnIUm4tzKJv2GmVWjpHavyH0dAbvZuikEoJegooB5n4cEjdH wwHxQ1k8tUbHZNIDWQNA==; Received: from localhost ([::1] helo=bombadil.infradead.org) by bombadil.infradead.org with esmtp (Exim 4.94.2 #2 (Red Hat Linux)) id 1nzH5h-001ehy-66; Thu, 09 Jun 2022 12:16:45 +0000 Received: from szxga08-in.huawei.com ([45.249.212.255]) by bombadil.infradead.org with esmtps (Exim 4.94.2 #2 (Red Hat Linux)) id 1nzGwp-001aad-7o for linux-arm-kernel@lists.infradead.org; Thu, 09 Jun 2022 12:07:40 +0000 Received: from canpemm500009.china.huawei.com (unknown [172.30.72.57]) by szxga08-in.huawei.com (SkyGuard) with ESMTP id 4LJjTv4hs4z1GCYh; Thu, 9 Jun 2022 20:05:39 +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, 9 Jun 2022 20:07:29 +0800 From: Yicong Yang To: , , , , , , , CC: , , , , , , , , , , <21cnbao@gmail.com>, , , , Subject: [PATCH v4 2/2] sched/fair: Scan cluster before scanning LLC in wake-up path Date: Thu, 9 Jun 2022 20:06:22 +0800 Message-ID: <20220609120622.47724-3-yangyicong@hisilicon.com> X-Mailer: git-send-email 2.31.0 In-Reply-To: <20220609120622.47724-1-yangyicong@hisilicon.com> References: <20220609120622.47724-1-yangyicong@hisilicon.com> MIME-Version: 1.0 X-Originating-IP: [10.67.164.66] X-ClientProxiedBy: dggems702-chm.china.huawei.com (10.3.19.179) 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-20220609_050735_731022_2B1FEBC3 X-CRM114-Status: GOOD ( 15.62 ) 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: , Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: 7bit 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: 5.19-rc1 patched Hmean 1 350.27 ( 0.00%) 406.88 * 16.16%* Hmean 2 702.01 ( 0.00%) 808.22 * 15.13%* Hmean 4 1405.14 ( 0.00%) 1614.34 * 14.89%* Hmean 8 2830.53 ( 0.00%) 3169.02 * 11.96%* Hmean 16 5597.95 ( 0.00%) 6224.20 * 11.19%* Hmean 32 10537.38 ( 0.00%) 10524.97 * -0.12%* Hmean 64 8366.04 ( 0.00%) 8437.41 * 0.85%* Hmean 128 7060.87 ( 0.00%) 7150.25 * 1.27%* On numa 0-1: 5.19-rc1 patched Hmean 1 346.11 ( 0.00%) 408.47 * 18.02%* Hmean 2 693.34 ( 0.00%) 805.78 * 16.22%* Hmean 4 1384.96 ( 0.00%) 1602.49 * 15.71%* Hmean 8 2699.45 ( 0.00%) 3069.98 * 13.73%* Hmean 16 5327.11 ( 0.00%) 5688.19 * 6.78%* Hmean 32 10019.10 ( 0.00%) 11862.56 * 18.40%* Hmean 64 13850.57 ( 0.00%) 17748.54 * 28.14%* Hmean 128 12498.25 ( 0.00%) 15541.59 * 24.35%* Hmean 256 11195.77 ( 0.00%) 13854.06 * 23.74%* Tested-by: Yicong Yang Signed-off-by: Barry Song Signed-off-by: Yicong Yang --- 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 77b2048a9326..6d173e196ad3 100644 --- a/kernel/sched/fair.c +++ b/kernel/sched/fair.c @@ -6327,6 +6327,40 @@ 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) + break; + + 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 @@ -6375,6 +6409,10 @@ static int select_idle_cpu(struct task_struct *p, struct sched_domain *sd, bool time = cpu_clock(this); } + 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); @@ -6382,7 +6420,7 @@ 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) @@ -6481,7 +6519,7 @@ 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_resources(prev, target) && (available_idle_cpu(prev) || sched_idle_cpu(prev)) && asym_fits_capacity(task_util, prev)) return prev; @@ -6507,7 +6545,7 @@ 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_resources(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)) { -- 2.24.0 _______________________________________________ linux-arm-kernel mailing list linux-arm-kernel@lists.infradead.org http://lists.infradead.org/mailman/listinfo/linux-arm-kernel