From patchwork Thu Sep 15 07:34:23 2022 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Yicong Yang X-Patchwork-Id: 12976976 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 D49FFECAAA1 for ; Thu, 15 Sep 2022 07:42:01 +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=qvo3vbVEOyCW7jgDajzSZeQuaNKLjjB8hGtp60u4fCg=; b=xVoyTmdfsyp68U MGw/r1T6uDlh/PxojNFPwO9XSQr1XC0PYzVKS7ZaI+zhPjfZh4GJyNf2V+WL5AAgmweF1tYQ0DU8x 8vYeyms4nWGjikqwVd2MYM2+ADUkE+8hsiTed5JPJduId70oQpOjA6kgoiGtnR1gB1ZxXALpT4NRL pxrN0xOyy9PT0vQ97xe1Zk9e0B24fqtGZdH4xdVBqv2V+ZttBjP4oXdbuj+astCFllKO1PqNOX5VN VCMw1XO3W2bBQ1qjCwzkYRbYtmVP8uuF2U2ar7Nfb45n0uBunaDQmyrzJ1avlZy0hm2FM4vEIF9KK xmhoSI5bAIUzVeHe9Wgg==; Received: from localhost ([::1] helo=bombadil.infradead.org) by bombadil.infradead.org with esmtp (Exim 4.94.2 #2 (Red Hat Linux)) id 1oYjUV-002xEh-5V; Thu, 15 Sep 2022 07:40:55 +0000 Received: from szxga01-in.huawei.com ([45.249.212.187]) by bombadil.infradead.org with esmtps (Exim 4.94.2 #2 (Red Hat Linux)) id 1oYjQb-002tfD-SN for linux-arm-kernel@lists.infradead.org; Thu, 15 Sep 2022 07:36:57 +0000 Received: from canpemm500009.china.huawei.com (unknown [172.30.72.54]) by szxga01-in.huawei.com (SkyGuard) with ESMTP id 4MSpnl6kgBzlVvf; Thu, 15 Sep 2022 15:32:43 +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 15.1.2375.31; Thu, 15 Sep 2022 15:36:42 +0800 From: Yicong Yang To: , , , , , , , CC: , , , , , , , , , , <21cnbao@gmail.com>, , , , , , , Subject: [RESEND PATCH v7 2/2] sched/fair: Scan cluster before scanning LLC in wake-up path Date: Thu, 15 Sep 2022 15:34:23 +0800 Message-ID: <20220915073423.25535-3-yangyicong@huawei.com> X-Mailer: git-send-email 2.31.0 In-Reply-To: <20220915073423.25535-1-yangyicong@huawei.com> References: <20220915073423.25535-1-yangyicong@huawei.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-20220915_003654_351272_FADD5559 X-CRM114-Status: GOOD ( 19.90 ) 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. 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: 6.0-rc1 patched Hmean 1 351.20 ( 0.00%) 396.45 * 12.88%* Hmean 2 700.43 ( 0.00%) 793.76 * 13.32%* Hmean 4 1404.42 ( 0.00%) 1583.62 * 12.76%* Hmean 8 2833.31 ( 0.00%) 3147.85 * 11.10%* Hmean 16 5501.90 ( 0.00%) 6089.89 * 10.69%* Hmean 32 10428.59 ( 0.00%) 10619.63 * 1.83%* Hmean 64 8223.39 ( 0.00%) 8306.93 * 1.02%* Hmean 128 7042.88 ( 0.00%) 7068.03 * 0.36%* On numa 0-1: 6.0-rc1 patched Hmean 1 363.06 ( 0.00%) 397.13 * 9.38%* Hmean 2 721.68 ( 0.00%) 789.84 * 9.44%* Hmean 4 1435.15 ( 0.00%) 1566.01 * 9.12%* Hmean 8 2776.17 ( 0.00%) 3007.05 * 8.32%* Hmean 16 5471.71 ( 0.00%) 6103.91 * 11.55%* Hmean 32 10164.98 ( 0.00%) 11531.81 * 13.45%* Hmean 64 17143.28 ( 0.00%) 20078.68 * 17.12%* Hmean 128 14552.70 ( 0.00%) 15156.41 * 4.15%* Hmean 256 12827.37 ( 0.00%) 13326.86 * 3.89%* Note neither Kunpeng920 nor x86 Jacobsville supports SMT, so the SMT branch in the code has not been tested but it supposed to work. Suggested-by: Peter Zijlstra [https://lore.kernel.org/lkml/Ytfjs+m1kUs0ScSn@worktop.programming.kicks-ass.net] Tested-by: Yicong Yang Signed-off-by: Barry Song Signed-off-by: Yicong Yang Reviewed-by: Tim Chen Reviewed-by: Chen Yu --- kernel/sched/fair.c | 30 +++++++++++++++++++++++++++--- kernel/sched/sched.h | 1 + kernel/sched/topology.c | 10 ++++++++++ 3 files changed, 38 insertions(+), 3 deletions(-) diff --git a/kernel/sched/fair.c b/kernel/sched/fair.c index 4e5b171b1171..e6505b0764c0 100644 --- a/kernel/sched/fair.c +++ b/kernel/sched/fair.c @@ -6444,6 +6444,30 @@ static int select_idle_cpu(struct task_struct *p, struct sched_domain *sd, bool } } + if (static_branch_unlikely(&sched_cluster_active)) { + struct sched_domain *sdc = rcu_dereference(per_cpu(sd_cluster, target)); + + if (sdc) { + for_each_cpu_wrap(cpu, sched_domain_span(sdc), target + 1) { + if (!cpumask_test_cpu(cpu, cpus)) + continue; + + if (has_idle_core) { + i = select_idle_core(p, cpu, cpus, &idle_cpu); + if ((unsigned int)i < nr_cpumask_bits) + return i; + } else { + if (--nr <= 0) + 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(sdc)); + } + } + for_each_cpu_wrap(cpu, cpus, target + 1) { if (has_idle_core) { i = select_idle_core(p, cpu, cpus, &idle_cpu); @@ -6451,7 +6475,7 @@ 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) @@ -6550,7 +6574,7 @@ 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; @@ -6576,7 +6600,7 @@ 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)) { diff --git a/kernel/sched/sched.h b/kernel/sched/sched.h index c148f6c4f0fc..f99208146d7a 100644 --- a/kernel/sched/sched.h +++ b/kernel/sched/sched.h @@ -1801,6 +1801,7 @@ DECLARE_PER_CPU(struct sched_domain __rcu *, sd_numa); DECLARE_PER_CPU(struct sched_domain __rcu *, sd_asym_packing); DECLARE_PER_CPU(struct sched_domain __rcu *, sd_asym_cpucapacity); extern struct static_key_false sched_asym_cpucapacity; +extern struct static_key_false sched_cluster_active; static __always_inline bool sched_asym_cpucap_active(void) { diff --git a/kernel/sched/topology.c b/kernel/sched/topology.c index 8ab27c0d6d1f..04ead3227201 100644 --- a/kernel/sched/topology.c +++ b/kernel/sched/topology.c @@ -670,7 +670,9 @@ DEFINE_PER_CPU(struct sched_domain_shared __rcu *, sd_llc_shared); DEFINE_PER_CPU(struct sched_domain __rcu *, sd_numa); DEFINE_PER_CPU(struct sched_domain __rcu *, sd_asym_packing); DEFINE_PER_CPU(struct sched_domain __rcu *, sd_asym_cpucapacity); + DEFINE_STATIC_KEY_FALSE(sched_asym_cpucapacity); +DEFINE_STATIC_KEY_FALSE(sched_cluster_active); static void update_top_cache_domain(int cpu) { @@ -2268,6 +2270,7 @@ build_sched_domains(const struct cpumask *cpu_map, struct sched_domain_attr *att struct rq *rq = NULL; int i, ret = -ENOMEM; bool has_asym = false; + bool has_cluster = false; if (WARN_ON(cpumask_empty(cpu_map))) goto error; @@ -2289,6 +2292,7 @@ build_sched_domains(const struct cpumask *cpu_map, struct sched_domain_attr *att sd = build_sched_domain(tl, cpu_map, attr, sd, i); has_asym |= sd->flags & SD_ASYM_CPUCAPACITY; + has_cluster |= sd->flags & SD_CLUSTER; if (tl == sched_domain_topology) *per_cpu_ptr(d.sd, i) = sd; @@ -2399,6 +2403,9 @@ build_sched_domains(const struct cpumask *cpu_map, struct sched_domain_attr *att if (has_asym) static_branch_inc_cpuslocked(&sched_asym_cpucapacity); + if (has_cluster) + static_branch_inc_cpuslocked(&sched_cluster_active); + if (rq && sched_debug_verbose) { pr_info("root domain span: %*pbl (max cpu_capacity = %lu)\n", cpumask_pr_args(cpu_map), rq->rd->max_cpu_capacity); @@ -2498,6 +2505,9 @@ static void detach_destroy_domains(const struct cpumask *cpu_map) if (rcu_access_pointer(per_cpu(sd_asym_cpucapacity, cpu))) static_branch_dec_cpuslocked(&sched_asym_cpucapacity); + if (rcu_access_pointer(per_cpu(sd_cluster, cpu))) + static_branch_dec_cpuslocked(&sched_cluster_active); + rcu_read_lock(); for_each_cpu(i, cpu_map) cpu_attach_domain(NULL, &def_root_domain, i);