From patchwork Wed Dec 15 04:11:49 2021 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Yicong Yang X-Patchwork-Id: 12696156 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 6FC58C433F5 for ; Wed, 15 Dec 2021 04:13:47 +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=eikShitSn8podUJcBwELfcSQLWTaZS2kHnxqi3EV74c=; b=t50X+BuuUdbaea AUyiFHKGjiQMVXKf3JBTpT9nKiQVTZ2SfTAvDEg9PIA6fAOPY98o3hEoDKQYCcR/zAwBG0FZfqFU+ aGPqF+5rYgKrUqjsUojMNXBaI1RCTLG7DLD+HlQicngLQlLSIOYQkt7+OWhZasL6c7cWgZa2H7EN/ Et1ABCdT7MhI1UWcUbablfbgetkOkGebPWi0xt2ERljO84mCiOhTEDnFiWD3h/mq4F7VgEwfQMrJc dzQQHcpVereVhWtI3sXIU7lbxtmLL4ZYdX//P/UnnkSogTZqvHDeZj7LN8HB+cM2VIYjhHx88uyDq E0ASuaIJZa+hG/MbAyrg==; Received: from localhost ([::1] helo=bombadil.infradead.org) by bombadil.infradead.org with esmtp (Exim 4.94.2 #2 (Red Hat Linux)) id 1mxLeT-00GcN6-SF; Wed, 15 Dec 2021 04:12:26 +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 1mxLe7-00GcHO-AB for linux-arm-kernel@lists.infradead.org; Wed, 15 Dec 2021 04:12:05 +0000 Received: from canpemm500009.china.huawei.com (unknown [172.30.72.56]) by szxga02-in.huawei.com (SkyGuard) with ESMTP id 4JDMJB6yKQzbjLQ; Wed, 15 Dec 2021 12:11:38 +0800 (CST) Received: from localhost.localdomain (10.67.165.103) 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 15.1.2308.20; Wed, 15 Dec 2021 12:11:56 +0800 From: Yicong Yang To: , , , , , , CC: , , , , , , , , , , <21cnbao@gmail.com>, , Subject: [PATCH 2/2] sched/fair: Scan cluster before scanning LLC in wake-up path Date: Wed, 15 Dec 2021 12:11:49 +0800 Message-ID: <20211215041149.73171-3-yangyicong@hisilicon.com> X-Mailer: git-send-email 2.31.0 In-Reply-To: <20211215041149.73171-1-yangyicong@hisilicon.com> References: <20211215041149.73171-1-yangyicong@hisilicon.com> MIME-Version: 1.0 X-Originating-IP: [10.67.165.103] X-ClientProxiedBy: dggems705-chm.china.huawei.com (10.3.19.182) 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-20211214_201203_746044_92D3C154 X-CRM114-Status: GOOD ( 15.81 ) 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. 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: 5.16-rc1 patched Hmean 1 329.17 ( 0.00%) 384.84 * 16.91%* Hmean 2 654.09 ( 0.00%) 768.77 * 17.53%* Hmean 4 1321.41 ( 0.00%) 1538.10 * 16.40%* Hmean 8 2650.43 ( 0.00%) 3048.86 * 15.03%* Hmean 16 5322.37 ( 0.00%) 5975.20 * 12.27%* Hmean 32 10002.11 ( 0.00%) 10085.57 * 0.83%* Hmean 64 7910.39 ( 0.00%) 7936.37 * 0.33%* Hmean 128 6745.25 ( 0.00%) 6811.28 * 0.98%* On numa 0-1: 5.16-rc1 patched Hmean 1 326.61 ( 0.00%) 385.36 * 17.99%* Hmean 2 650.62 ( 0.00%) 770.57 * 18.44%* Hmean 4 1318.05 ( 0.00%) 1534.83 * 16.45%* Hmean 8 2621.50 ( 0.00%) 3030.10 * 15.59%* Hmean 16 5252.17 ( 0.00%) 6023.08 * 14.68%* Hmean 32 9829.30 ( 0.00%) 9856.33 * 0.28%* Hmean 64 12452.66 ( 0.00%) 17338.48 * 39.24%* Hmean 128 14181.24 ( 0.00%) 15025.24 * 5.95%* Hmean 256 12239.07 ( 0.00%) 13080.16 * 6.87%* Hmean 512 14297.00 ( 0.00%) 15063.76 * 5.36%* This will also help to improve the MySQL. With MySQL server running on numa 0 and client running on numa 1, both QPS and latency is imporved on read-write case: 5.16-rc1 patched QPS-24threads 195327.48 202081.28(+3.46%) QPS-32threads 242039.4 247059.5(+2.07%) QPS-64threads 243024.52 254274.47(+4.63%) avg-lat-24threads 2.46 2.37(+3.66%) avg-lat-36threads 2.64 2.59(+1.89%) avg-lat-64threads 5.27 5.03(+4.55%) Tested-by: Yicong Yang Signed-off-by: Barry Song Signed-off-by: Yicong Yang --- kernel/sched/fair.c | 46 +++++++++++++++++++++++++++++++++++++++++---- 1 file changed, 42 insertions(+), 4 deletions(-) diff --git a/kernel/sched/fair.c b/kernel/sched/fair.c index 6e476f6d9435..8a5795c78af8 100644 --- a/kernel/sched/fair.c +++ b/kernel/sched/fair.c @@ -6230,12 +6230,46 @@ 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, int prev_cpu, int target) +{ + struct cpumask *cpus = this_cpu_cpumask_var_ptr(select_idle_mask); + struct sched_domain *sd = rcu_dereference(per_cpu(sd_cluster, target)); + int cpu, idle_cpu; + + /* TODO: Support SMT case while a machine with both cluster and SMT born */ + if (!sched_smt_active() && sd) { + for_each_cpu_and(cpu, cpus, sched_domain_span(sd)) { + idle_cpu = __select_idle_cpu(cpu, p); + if ((unsigned int)idle_cpu < nr_cpumask_bits) + return idle_cpu; + } + + /* Don't ping-pong tasks in and out cluster frequently */ + if (cpus_share_cluster(target, prev_cpu)) + return target; + + cpumask_andnot(cpus, cpus, sched_domain_span(sd)); + } + + return -1; +} +#else +static inline int scan_cluster(struct task_struct *p, int prev_cpu, int target) +{ + 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 * average idle time for this rq (as found in rq->avg_idle). */ -static int select_idle_cpu(struct task_struct *p, struct sched_domain *sd, bool has_idle_core, int target) +static int select_idle_cpu(struct task_struct *p, struct sched_domain *sd, bool has_idle_core, int prev_cpu, int target) { struct cpumask *cpus = this_cpu_cpumask_var_ptr(select_idle_mask); int i, cpu, idle_cpu = -1, nr = INT_MAX; @@ -6250,6 +6284,10 @@ static int select_idle_cpu(struct task_struct *p, struct sched_domain *sd, bool cpumask_and(cpus, sched_domain_span(sd), p->cpus_ptr); + idle_cpu = scan_cluster(p, prev_cpu, target); + if ((unsigned int)idle_cpu < nr_cpumask_bits) + return idle_cpu; + if (sched_feat(SIS_PROP) && !has_idle_core) { u64 avg_cost, avg_idle, span_avg; unsigned long now = jiffies; @@ -6384,7 +6422,7 @@ 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_cluster(prev, target) && (available_idle_cpu(prev) || sched_idle_cpu(prev)) && asym_fits_capacity(task_util, prev)) return prev; @@ -6408,7 +6446,7 @@ 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_cluster(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)) { @@ -6449,7 +6487,7 @@ static int select_idle_sibling(struct task_struct *p, int prev, int target) } } - i = select_idle_cpu(p, sd, has_idle_core, target); + i = select_idle_cpu(p, sd, has_idle_core, prev, target); if ((unsigned)i < nr_cpumask_bits) return i;