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[209.132.180.67]) by mx.google.com with ESMTP id j14si4683323eda.181.2019.09.19.00.34.09; Thu, 19 Sep 2019 00:34:09 -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=IkJ83N0y; 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 S2388639AbfISHeF (ORCPT + 26 others); Thu, 19 Sep 2019 03:34:05 -0400 Received: from mail-wr1-f66.google.com ([209.85.221.66]:46809 "EHLO mail-wr1-f66.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S2388627AbfISHeE (ORCPT ); Thu, 19 Sep 2019 03:34:04 -0400 Received: by mail-wr1-f66.google.com with SMTP id o18so1873628wrv.13 for ; Thu, 19 Sep 2019 00:34:02 -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=vT3Cd0NoScWU8B4s0yMOgG1KA81Kqbh6T7GDIZMysSg=; b=IkJ83N0ynH6XKiHk3CQil2ckbXxjqo5pUHPS6taYyJRDS8qrGC9+tyFOB+7M84gGKo wTSGVdxZ5ZjvvMC3XiD5bdflf3YR+EOkG59XaRaAZIqkg22WJrWmkYrIhzv2n9nSfMek DE1q0JyvpkVb5PsKAbI3keJvgI3EyKv+6VbzthFqjwbq3uDyir+p/P4/t07DDT2HGj56 vXY83lcVveh2vl+JgFFIl6NtjpiTEUO36IPe8TAYZ9Res/U3AZMANGDGzSAneDFzXGAC 9FRepOWBk+rJyynJyoMroEBHJ7Y34W4bSOM0AgWCsA02jwgUbdCSycd5P27mwOjl8d5h 9aZA== 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=vT3Cd0NoScWU8B4s0yMOgG1KA81Kqbh6T7GDIZMysSg=; b=oLQkCo530jWlt7aAD93piJqdOC7xmkW5+o5n/1Q7Hv/9vAAUmDYGebKn4Uc6TJg26n g6aSoj45jnDmAfmsxfaeGYyVi1K1UMACTvPH3uGmszALLym7vUpPUpF4JAWoJaylMge2 YWzBgpDSwqWTJZSkdAPnhaetPY0DYOvqGR85Q+D+O6qlkRkGelAJ9f02h+dMENAjMFMV zG4D6A+zeOxbi/TeeD7bQTQJIxXiLy1lAJhn7yJHTIPF/Eia8mONxRX9y84X/p/9sX/F seANIgl+USYPka0nqk7M5HIjShgwZwhFCog9oD/643w6SWTGgjKzMpBYUfkcjc6gCHL1 7zpQ== X-Gm-Message-State: APjAAAVYEU58QFfUIIGEurv8GjsRBm7MNnu3hVq2Pw73o5LjpSN0Th9O qDzise5F3W0u64LFu3RYxKMebLRC0Y0= X-Received: by 2002:adf:f601:: with SMTP id t1mr5958913wrp.36.1568878441506; Thu, 19 Sep 2019 00:34:01 -0700 (PDT) Received: from localhost.localdomain ([2a01:e0a:f:6020:d555:8fca:a19c:222c]) by smtp.gmail.com with ESMTPSA id s12sm13300250wra.82.2019.09.19.00.33.59 (version=TLS1_2 cipher=ECDHE-RSA-AES128-SHA bits=128/128); Thu, 19 Sep 2019 00:33:59 -0700 (PDT) From: Vincent Guittot To: linux-kernel@vger.kernel.org, mingo@redhat.com, peterz@infradead.org Cc: pauld@redhat.com, valentin.schneider@arm.com, srikar@linux.vnet.ibm.com, quentin.perret@arm.com, dietmar.eggemann@arm.com, Morten.Rasmussen@arm.com, hdanton@sina.com, Vincent Guittot Subject: [PATCH v3 03/10] sched/fair: remove meaningless imbalance calculation Date: Thu, 19 Sep 2019 09:33:34 +0200 Message-Id: <1568878421-12301-4-git-send-email-vincent.guittot@linaro.org> X-Mailer: git-send-email 2.7.4 In-Reply-To: <1568878421-12301-1-git-send-email-vincent.guittot@linaro.org> References: <1568878421-12301-1-git-send-email-vincent.guittot@linaro.org> Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org clean up load_balance and remove meaningless calculation and fields before adding new algorithm. Signed-off-by: Vincent Guittot --- kernel/sched/fair.c | 105 +--------------------------------------------------- 1 file changed, 1 insertion(+), 104 deletions(-) -- 2.7.4 Acked-by: Rik van Riel Reviewed-by: Valentin Schneider diff --git a/kernel/sched/fair.c b/kernel/sched/fair.c index 02ab6b5..017aad0 100644 --- a/kernel/sched/fair.c +++ b/kernel/sched/fair.c @@ -5390,18 +5390,6 @@ static unsigned long capacity_of(int cpu) return cpu_rq(cpu)->cpu_capacity; } -static unsigned long cpu_avg_load_per_task(int cpu) -{ - struct rq *rq = cpu_rq(cpu); - unsigned long nr_running = READ_ONCE(rq->cfs.h_nr_running); - unsigned long load_avg = cpu_runnable_load(rq); - - if (nr_running) - return load_avg / nr_running; - - return 0; -} - static void record_wakee(struct task_struct *p) { /* @@ -7677,7 +7665,6 @@ static unsigned long task_h_load(struct task_struct *p) struct sg_lb_stats { unsigned long avg_load; /*Avg load across the CPUs of the group */ unsigned long group_load; /* Total load over the CPUs of the group */ - unsigned long load_per_task; unsigned long group_capacity; unsigned long group_util; /* Total utilization of the group */ unsigned int sum_h_nr_running; /* Nr of CFS tasks running in the group */ @@ -8059,9 +8046,6 @@ static inline void update_sg_lb_stats(struct lb_env *env, sgs->group_capacity = group->sgc->capacity; sgs->avg_load = (sgs->group_load*SCHED_CAPACITY_SCALE) / sgs->group_capacity; - if (sgs->sum_h_nr_running) - sgs->load_per_task = sgs->group_load / sgs->sum_h_nr_running; - sgs->group_weight = group->group_weight; sgs->group_no_capacity = group_is_overloaded(env, sgs); @@ -8292,76 +8276,6 @@ static inline void update_sd_lb_stats(struct lb_env *env, struct sd_lb_stats *sd } /** - * fix_small_imbalance - Calculate the minor imbalance that exists - * amongst the groups of a sched_domain, during - * load balancing. - * @env: The load balancing environment. - * @sds: Statistics of the sched_domain whose imbalance is to be calculated. - */ -static inline -void fix_small_imbalance(struct lb_env *env, struct sd_lb_stats *sds) -{ - unsigned long tmp, capa_now = 0, capa_move = 0; - unsigned int imbn = 2; - unsigned long scaled_busy_load_per_task; - struct sg_lb_stats *local, *busiest; - - local = &sds->local_stat; - busiest = &sds->busiest_stat; - - if (!local->sum_h_nr_running) - local->load_per_task = cpu_avg_load_per_task(env->dst_cpu); - else if (busiest->load_per_task > local->load_per_task) - imbn = 1; - - scaled_busy_load_per_task = - (busiest->load_per_task * SCHED_CAPACITY_SCALE) / - busiest->group_capacity; - - if (busiest->avg_load + scaled_busy_load_per_task >= - local->avg_load + (scaled_busy_load_per_task * imbn)) { - env->imbalance = busiest->load_per_task; - return; - } - - /* - * OK, we don't have enough imbalance to justify moving tasks, - * however we may be able to increase total CPU capacity used by - * moving them. - */ - - capa_now += busiest->group_capacity * - min(busiest->load_per_task, busiest->avg_load); - capa_now += local->group_capacity * - min(local->load_per_task, local->avg_load); - capa_now /= SCHED_CAPACITY_SCALE; - - /* Amount of load we'd subtract */ - if (busiest->avg_load > scaled_busy_load_per_task) { - capa_move += busiest->group_capacity * - min(busiest->load_per_task, - busiest->avg_load - scaled_busy_load_per_task); - } - - /* Amount of load we'd add */ - if (busiest->avg_load * busiest->group_capacity < - busiest->load_per_task * SCHED_CAPACITY_SCALE) { - tmp = (busiest->avg_load * busiest->group_capacity) / - local->group_capacity; - } else { - tmp = (busiest->load_per_task * SCHED_CAPACITY_SCALE) / - local->group_capacity; - } - capa_move += local->group_capacity * - min(local->load_per_task, local->avg_load + tmp); - capa_move /= SCHED_CAPACITY_SCALE; - - /* Move if we gain throughput */ - if (capa_move > capa_now) - env->imbalance = busiest->load_per_task; -} - -/** * calculate_imbalance - Calculate the amount of imbalance present within the * groups of a given sched_domain during load balance. * @env: load balance environment @@ -8380,15 +8294,6 @@ static inline void calculate_imbalance(struct lb_env *env, struct sd_lb_stats *s return; } - if (busiest->group_type == group_imbalanced) { - /* - * In the group_imb case we cannot rely on group-wide averages - * to ensure CPU-load equilibrium, look at wider averages. XXX - */ - busiest->load_per_task = - min(busiest->load_per_task, sds->avg_load); - } - /* * Avg load of busiest sg can be less and avg load of local sg can * be greater than avg load across all sgs of sd because avg load @@ -8399,7 +8304,7 @@ static inline void calculate_imbalance(struct lb_env *env, struct sd_lb_stats *s (busiest->avg_load <= sds->avg_load || local->avg_load >= sds->avg_load)) { env->imbalance = 0; - return fix_small_imbalance(env, sds); + return; } /* @@ -8437,14 +8342,6 @@ static inline void calculate_imbalance(struct lb_env *env, struct sd_lb_stats *s busiest->group_misfit_task_load); } - /* - * if *imbalance is less than the average load per runnable task - * there is no guarantee that any tasks will be moved so we'll have - * a think about bumping its value to force at least one task to be - * moved - */ - if (env->imbalance < busiest->load_per_task) - return fix_small_imbalance(env, sds); } /******* find_busiest_group() helpers end here *********************/