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[209.132.180.67]) by mx.google.com with ESMTP id m21si17710589pgl.45.2019.06.03.07.17.54; Mon, 03 Jun 2019 07:17:54 -0700 (PDT) Received-SPF: pass (google.com: best guess record for domain of linux-kernel-owner@vger.kernel.org designates 209.132.180.67 as permitted sender) client-ip=209.132.180.67; Authentication-Results: mx.google.com; dkim=pass header.i=@linaro.org header.s=google header.b=LDRhQ0Gx; spf=pass (google.com: best guess record for domain of linux-kernel-owner@vger.kernel.org designates 209.132.180.67 as permitted sender) smtp.mailfrom=linux-kernel-owner@vger.kernel.org; dmarc=pass (p=NONE sp=NONE dis=NONE) header.from=linaro.org Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1728974AbfFCORx (ORCPT + 30 others); Mon, 3 Jun 2019 10:17:53 -0400 Received: from mail-wr1-f66.google.com ([209.85.221.66]:45811 "EHLO mail-wr1-f66.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1726968AbfFCORx (ORCPT ); Mon, 3 Jun 2019 10:17:53 -0400 Received: by mail-wr1-f66.google.com with SMTP id b18so12237991wrq.12 for ; Mon, 03 Jun 2019 07:17:51 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=linaro.org; s=google; h=from:to:cc:subject:date:message-id:in-reply-to:references; bh=KAC1TPImFCotEdm440j6roz5khMTaZly6qZwqAJTL0A=; b=LDRhQ0GxAoaa1xYNU4bz3whjgV7vMOulgp/7oUEDzyvF8DLe0pfMjqEe10lV/lqUfc +ZtEDT0u7T9s83JNDJ0F7oq2faHUKT2SJnyTvYAMtKVHFIZgqU0TLgoMiy0SrxLqhpa2 n4tdIntutujIZ0gsJLtaZP0/sTaaAJoVnBYqbpKf0Rirrqeb7upWpqbGufFLtWmr9Ob6 6HmRtxjPOR/K6t0jSclptjufcYSPAZNeQCygRFuViBMTAnbO5I0rjjorjjb1oEgFR2F+ fVpeuegHf3KL00J9pNVBRw/C4MVmQ6Xp36Dut5b5bUBDStdWjrGHFse6XS8xFCX1hxuX KfNw== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20161025; h=x-gm-message-state:from:to:cc:subject:date:message-id:in-reply-to :references; bh=KAC1TPImFCotEdm440j6roz5khMTaZly6qZwqAJTL0A=; b=YXS+A9erEK3x+uYJoKLRVKWBnXJrwzDsWLVN0hJRY1co3hp9xBfFJLtRCb/mJuy5Ib dRmjSsYB1UIjENwB8nbdG3QEyfPP1pdMJSmvnPV5YCWlcVGaFObtRLa5eNazg1eNhJhp jvqUU9QsOZd9+lbDIfkj+3OtGb69SFNeAL16mrHIkpsLCCxUREd/w1QbQacjmofQhMeX njrfrgha/SzFQsdH/kZramOI9+Ov5kF+PxJbAEw17n3F1UHKoEGBxjsAp9UFzNYtMtU4 kncVe8GSHwg8LarZdR1lywJyjDb6qpa5It4H+maM3W0M4DQqx/PSCgsmE5Dm2NsO4Afi bcTQ== X-Gm-Message-State: APjAAAV8gGBp8tNdxNMzezFLM9NOtCXXiYbJCmvL8Rx0VPhEQkUI7oMA rJ8+TyNE7fzRfQxan6Nw65NSAw== X-Received: by 2002:a5d:56c1:: with SMTP id m1mr17394223wrw.26.1559571470222; Mon, 03 Jun 2019 07:17:50 -0700 (PDT) Received: from localhost.localdomain ([2a01:e0a:f:6020:8816:b980:b875:4d47]) by smtp.gmail.com with ESMTPSA id h8sm7116223wrt.59.2019.06.03.07.17.49 (version=TLS1_2 cipher=ECDHE-RSA-AES128-SHA bits=128/128); Mon, 03 Jun 2019 07:17:49 -0700 (PDT) From: Vincent Guittot To: mingo@redhat.com, peterz@infradead.org, linux-kernel@vger.kernel.org Cc: Vincent Guittot Subject: [PATCH] sched/fair: clean up asym packing Date: Mon, 3 Jun 2019 16:17:16 +0200 Message-Id: <1559571436-29091-1-git-send-email-vincent.guittot@linaro.org> X-Mailer: git-send-email 2.7.4 In-Reply-To: <1559571064-28087-1-git-send-email-vincent.guitto@linaro.org> References: <1559571064-28087-1-git-send-email-vincent.guitto@linaro.org> Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Clean up asym packing to follow the default load balance behavior: - classify the group by creating a group_asym_capacity field. - calculate the imbalance in calculate_imbalance() instead of bypassing it. We don't need to test twice same conditions anymore to detect asym packing and we consolidate the calculation of imbalance in calculate_imbalance(). There is no functional changes. Signed-off-by: Vincent Guittot --- kernel/sched/fair.c | 63 ++++++++++++++--------------------------------------- 1 file changed, 16 insertions(+), 47 deletions(-) -- 2.7.4 diff --git a/kernel/sched/fair.c b/kernel/sched/fair.c index f35930f..93c2447 100644 --- a/kernel/sched/fair.c +++ b/kernel/sched/fair.c @@ -7888,6 +7888,7 @@ struct sg_lb_stats { unsigned int group_weight; enum group_type group_type; int group_no_capacity; + int group_asym_capacity; unsigned long group_misfit_task_load; /* A CPU has a task too big for its capacity */ #ifdef CONFIG_NUMA_BALANCING unsigned int nr_numa_running; @@ -8382,9 +8383,17 @@ static bool update_sd_pick_busiest(struct lb_env *env, * ASYM_PACKING needs to move all the work to the highest * prority CPUs in the group, therefore mark all groups * of lower priority than ourself as busy. + * + * This is primarily intended to used at the sibling level. Some + * cores like POWER7 prefer to use lower numbered SMT threads. In the + * case of POWER7, it can move to lower SMT modes only when higher + * threads are idle. When in lower SMT modes, the threads will + * perform better since they share less core resources. Hence when we + * have idle threads, we want them to be the higher ones. */ if (sgs->sum_nr_running && sched_asym_prefer(env->dst_cpu, sg->asym_prefer_cpu)) { + sgs->group_asym_capacity = 1; if (!sds->busiest) return true; @@ -8522,51 +8531,6 @@ static inline void update_sd_lb_stats(struct lb_env *env, struct sd_lb_stats *sd } /** - * check_asym_packing - Check to see if the group is packed into the - * sched domain. - * - * This is primarily intended to used at the sibling level. Some - * cores like POWER7 prefer to use lower numbered SMT threads. In the - * case of POWER7, it can move to lower SMT modes only when higher - * threads are idle. When in lower SMT modes, the threads will - * perform better since they share less core resources. Hence when we - * have idle threads, we want them to be the higher ones. - * - * This packing function is run on idle threads. It checks to see if - * the busiest CPU in this domain (core in the P7 case) has a higher - * CPU number than the packing function is being run on. Here we are - * assuming lower CPU number will be equivalent to lower a SMT thread - * number. - * - * Return: 1 when packing is required and a task should be moved to - * this CPU. The amount of the imbalance is returned in env->imbalance. - * - * @env: The load balancing environment. - * @sds: Statistics of the sched_domain which is to be packed - */ -static int check_asym_packing(struct lb_env *env, struct sd_lb_stats *sds) -{ - int busiest_cpu; - - if (!(env->sd->flags & SD_ASYM_PACKING)) - return 0; - - if (env->idle == CPU_NOT_IDLE) - return 0; - - if (!sds->busiest) - return 0; - - busiest_cpu = sds->busiest->asym_prefer_cpu; - if (sched_asym_prefer(busiest_cpu, env->dst_cpu)) - return 0; - - env->imbalance = sds->busiest_stat.group_load; - - return 1; -} - -/** * fix_small_imbalance - Calculate the minor imbalance that exists * amongst the groups of a sched_domain, during * load balancing. @@ -8650,6 +8614,11 @@ static inline void calculate_imbalance(struct lb_env *env, struct sd_lb_stats *s local = &sds->local_stat; busiest = &sds->busiest_stat; + if (busiest->group_asym_capacity) { + env->imbalance = busiest->group_load; + return; + } + if (busiest->group_type == group_imbalanced) { /* * In the group_imb case we cannot rely on group-wide averages @@ -8754,8 +8723,8 @@ static struct sched_group *find_busiest_group(struct lb_env *env) busiest = &sds.busiest_stat; /* ASYM feature bypasses nice load balance check */ - if (check_asym_packing(env, &sds)) - return sds.busiest; + if (busiest->group_asym_capacity) + goto force_balance; /* There is no busy sibling group to pull tasks from */ if (!sds.busiest || busiest->sum_nr_running == 0)