From patchwork Tue Jul 26 07:47:58 2022 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Yicong Yang X-Patchwork-Id: 12928999 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 44F11C43334 for ; Tue, 26 Jul 2022 07:57:00 +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=2AyD7F3bZOmBbH010MN8MOpYSj/PO1Dbn3LWu2IyarM=; b=PSUoe1ntEVc4XB 3fk8B4e6cBuPuY0Z+9myT3vaJFhWhn6MqzHz6/BvLP+mYVHwP3E2wPcH161R6h8QS6ENs1bkF4G4N 5AQmJDTmipRhTM5WUH7SxmJFs4gouHJUrATM21Ja4PQ3kAQv3754xDIJJmv0Ndn7rZYQUQplwcJdl qzPNGUrYvUNdMBCjZGrCN716HggELcT2/kEEFzjgzPxWD8ehZvTq9EpTtOBG8I3LRGr5HF2kgW5/3 piaaYbZn7aSkkxeyAQtqhzy6kqrZM/rfBiamJ8VSbIqXUtbLPZ+q9RL1CppBRrJOpxJ6szBfCasPX BCJsLG2cCYhbl1svNerw==; Received: from localhost ([::1] helo=bombadil.infradead.org) by bombadil.infradead.org with esmtp (Exim 4.94.2 #2 (Red Hat Linux)) id 1oGFPs-009iGF-22; Tue, 26 Jul 2022 07:55:44 +0000 Received: from szxga03-in.huawei.com ([45.249.212.189]) by bombadil.infradead.org with esmtps (Exim 4.94.2 #2 (Red Hat Linux)) id 1oGFKB-009dqE-4e for linux-arm-kernel@lists.infradead.org; Tue, 26 Jul 2022 07:49:55 +0000 Received: from canpemm500009.china.huawei.com (unknown [172.30.72.56]) by szxga03-in.huawei.com (SkyGuard) with ESMTP id 4LsTYW3VW9z9svw; Tue, 26 Jul 2022 15:48:31 +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; Tue, 26 Jul 2022 15:49:40 +0800 From: Yicong Yang To: , , , , , , , CC: , , , , , , , , , , <21cnbao@gmail.com>, , , , , , , Subject: [PATCH v6 2/2] sched/fair: Scan cluster before scanning LLC in wake-up path Date: Tue, 26 Jul 2022 15:47:58 +0800 Message-ID: <20220726074758.46686-3-yangyicong@huawei.com> X-Mailer: git-send-email 2.31.0 In-Reply-To: <20220726074758.46686-1-yangyicong@huawei.com> References: <20220726074758.46686-1-yangyicong@huawei.com> MIME-Version: 1.0 X-Originating-IP: [10.67.164.66] X-ClientProxiedBy: dggems704-chm.china.huawei.com (10.3.19.181) 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-20220726_004951_567847_D10ADAE5 X-CRM114-Status: GOOD ( 18.91 ) 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: tip/sched/core patched Hmean 1 345.89 ( 0.00%) 398.43 * 15.19%* Hmean 2 697.77 ( 0.00%) 794.40 * 13.85%* Hmean 4 1392.51 ( 0.00%) 1577.60 * 13.29%* Hmean 8 2800.61 ( 0.00%) 3118.38 * 11.35%* Hmean 16 5514.27 ( 0.00%) 6124.51 * 11.07%* Hmean 32 10869.81 ( 0.00%) 10690.97 * -1.65%* Hmean 64 8315.22 ( 0.00%) 8520.73 * 2.47%* Hmean 128 6324.47 ( 0.00%) 7253.65 * 14.69%* On numa 0-1: tip/sched/core patched Hmean 1 348.68 ( 0.00%) 397.74 * 14.07%* Hmean 2 693.57 ( 0.00%) 795.54 * 14.70%* Hmean 4 1369.26 ( 0.00%) 1548.72 * 13.11%* Hmean 8 2772.99 ( 0.00%) 3055.54 * 10.19%* Hmean 16 4825.83 ( 0.00%) 5936.64 * 23.02%* Hmean 32 10250.32 ( 0.00%) 11780.59 * 14.93%* Hmean 64 16309.51 ( 0.00%) 19864.38 * 21.80%* Hmean 128 13022.32 ( 0.00%) 16365.43 * 25.67%* Hmean 256 11335.79 ( 0.00%) 13991.33 * 23.43%* 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 --- kernel/sched/fair.c | 31 ++++++++++++++++++++++++++++--- kernel/sched/sched.h | 2 ++ kernel/sched/topology.c | 10 ++++++++++ 3 files changed, 40 insertions(+), 3 deletions(-) diff --git a/kernel/sched/fair.c b/kernel/sched/fair.c index 2fc47257ae91..1100fbf7baaf 100644 --- a/kernel/sched/fair.c +++ b/kernel/sched/fair.c @@ -6437,6 +6437,31 @@ static int select_idle_cpu(struct task_struct *p, struct sched_domain *sd, bool } } + if (IS_ENABLED(CONFIG_SCHED_CLUSTER) && + 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); @@ -6444,7 +6469,7 @@ 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) @@ -6543,7 +6568,7 @@ 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; @@ -6569,7 +6594,7 @@ 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 845cd029d572..4f0d3a74a532 100644 --- a/kernel/sched/sched.h +++ b/kernel/sched/sched.h @@ -1808,7 +1808,9 @@ DECLARE_PER_CPU(struct sched_domain __rcu *, sd_cluster); 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; struct sched_group_capacity { atomic_t ref; 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);