From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org X-Spam-Level: X-Spam-Status: No, score=-9.8 required=3.0 tests=DKIM_SIGNED,DKIM_VALID, DKIM_VALID_AU,HEADER_FROM_DIFFERENT_DOMAINS,INCLUDES_PATCH,MAILING_LIST_MULTI, SIGNED_OFF_BY,SPF_HELO_NONE,SPF_PASS,URIBL_BLOCKED,USER_AGENT_GIT autolearn=ham autolearn_force=no version=3.4.0 Received: from mail.kernel.org (mail.kernel.org [198.145.29.99]) by smtp.lore.kernel.org (Postfix) with ESMTP id 96D89C49ED7 for ; Thu, 19 Sep 2019 07:34:20 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id 5F5DF21924 for ; Thu, 19 Sep 2019 07:34:20 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=pass (2048-bit key) header.d=linaro.org header.i=@linaro.org header.b="ytdXnKLO" Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S2388705AbfISHeT (ORCPT ); Thu, 19 Sep 2019 03:34:19 -0400 Received: from mail-wr1-f65.google.com ([209.85.221.65]:44502 "EHLO mail-wr1-f65.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S2388685AbfISHeR (ORCPT ); Thu, 19 Sep 2019 03:34:17 -0400 Received: by mail-wr1-f65.google.com with SMTP id i18so1883807wru.11 for ; Thu, 19 Sep 2019 00:34:15 -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=G38Beoqh46tSkk9feTTalhF9YSEcEpI24Anrd1Kl34E=; b=ytdXnKLOw7tyOpXbn4f94AyPbvdEkIJ7jwf1d/tJKiU5sjIzlgVtIZL2lgmxoNqKYk T4lGkWHf6yrp/1AtWR2IIlqKJ+lexzWecwblAecG+xVH4SDYZD4XsYbuc8469OLtdeNf kmLkqQR2twsWELCby55o28FgPGbRNSia6dCNeKWEeQnWzrk5qn6+fy62+mX2zQph18Sy J+xle92Rxh+kidq8JSP/FTxdyD458kWYcAxcZrdM6JGGm3eURpLIDjjX85isS4TPCfcv IPFDoMS/yzf0810SpaRTShFS2jzigstH6B66XkP7XGQZ/XbFB3uPgUITFJkfc0n7TYab D3vg== 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=G38Beoqh46tSkk9feTTalhF9YSEcEpI24Anrd1Kl34E=; b=B8KHXY0Skz/2I750pORRd+gWAVKbwM/4cWrSsv4aC2F0x42PM+nCL/qd7WWNB1dfAw MFxD6xHvCv7E65bjhK4KuaV6TsvM1wwJakVZ09Q9ONVkEE572AcE8ojuhCCf/xJp2ND3 3d+sNHMCa3njIy2O5WEDu4SaMq0ff3DJZdOHr6oBUecUvI3tOqWBNDwtD967SwZBOfgy PCddi0Ojow+7qX7WGAWmf4Tphzz0r2SP2yuePd7FZX9KTwmtr4K8xm7ztks57dTO7H+r eTMRrHNTIWI3z2VDR0O5Oh80lDAUeIhVNEOQG5QGK93cFPwcQyLdxQtvAhNZRhorwxZD kWAA== X-Gm-Message-State: APjAAAWxzIzPyD9WLBrj5laXrluduTFneDb6tymIqCot1wJ3zkeums1b NDoc01ePWxNwKwzfHhhATRHnxYyOLWs= X-Google-Smtp-Source: APXvYqwsoy3CDWPV0gmgWOyNo+VQl3JFNwXEvvfO6ywGpjfRAwZgPSq3IM6Flzqm0ceG+zd1h3IaDw== X-Received: by 2002:adf:904f:: with SMTP id h73mr6287470wrh.128.1568878454611; Thu, 19 Sep 2019 00:34:14 -0700 (PDT) Received: from localhost.localdomain ([2a01:e0a:f:6020:d555:8fca:a19c:222c]) by smtp.gmail.com with ESMTPSA id s12sm13300250wra.82.2019.09.19.00.34.13 (version=TLS1_2 cipher=ECDHE-RSA-AES128-SHA bits=128/128); Thu, 19 Sep 2019 00:34:13 -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 10/10] sched/fair: optimize find_idlest_group Date: Thu, 19 Sep 2019 09:33:41 +0200 Message-Id: <1568878421-12301-11-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 find_idlest_group() now loads CPU's load_avg in 2 different ways. Consolidate the function to read and use load_avg only once and simplify the algorithm to only look for the group with lowest load_avg. Signed-off-by: Vincent Guittot --- kernel/sched/fair.c | 52 +++++++++++----------------------------------------- 1 file changed, 11 insertions(+), 41 deletions(-) diff --git a/kernel/sched/fair.c b/kernel/sched/fair.c index 39a37ae..1fac444 100644 --- a/kernel/sched/fair.c +++ b/kernel/sched/fair.c @@ -5560,16 +5560,14 @@ find_idlest_group(struct sched_domain *sd, struct task_struct *p, { struct sched_group *idlest = NULL, *group = sd->groups; struct sched_group *most_spare_sg = NULL; - unsigned long min_runnable_load = ULONG_MAX; - unsigned long this_runnable_load = ULONG_MAX; - unsigned long min_avg_load = ULONG_MAX, this_avg_load = ULONG_MAX; + unsigned long min_load = ULONG_MAX, this_load = ULONG_MAX; unsigned long most_spare = 0, this_spare = 0; int imbalance_scale = 100 + (sd->imbalance_pct-100)/2; unsigned long imbalance = scale_load_down(NICE_0_LOAD) * (sd->imbalance_pct-100) / 100; do { - unsigned long load, avg_load, runnable_load; + unsigned long load; unsigned long spare_cap, max_spare_cap; int local_group; int i; @@ -5586,15 +5584,11 @@ find_idlest_group(struct sched_domain *sd, struct task_struct *p, * Tally up the load of all CPUs in the group and find * the group containing the CPU with most spare capacity. */ - avg_load = 0; - runnable_load = 0; + load = 0; max_spare_cap = 0; for_each_cpu(i, sched_group_span(group)) { - load = cpu_load(cpu_rq(i)); - runnable_load += load; - - avg_load += cfs_rq_load_avg(&cpu_rq(i)->cfs); + load += cpu_load(cpu_rq(i)); spare_cap = capacity_spare_without(i, p); @@ -5603,31 +5597,15 @@ find_idlest_group(struct sched_domain *sd, struct task_struct *p, } /* Adjust by relative CPU capacity of the group */ - avg_load = (avg_load * SCHED_CAPACITY_SCALE) / - group->sgc->capacity; - runnable_load = (runnable_load * SCHED_CAPACITY_SCALE) / + load = (load * SCHED_CAPACITY_SCALE) / group->sgc->capacity; if (local_group) { - this_runnable_load = runnable_load; - this_avg_load = avg_load; + this_load = load; this_spare = max_spare_cap; } else { - if (min_runnable_load > (runnable_load + imbalance)) { - /* - * The runnable load is significantly smaller - * so we can pick this new CPU: - */ - min_runnable_load = runnable_load; - min_avg_load = avg_load; - idlest = group; - } else if ((runnable_load < (min_runnable_load + imbalance)) && - (100*min_avg_load > imbalance_scale*avg_load)) { - /* - * The runnable loads are close so take the - * blocked load into account through avg_load: - */ - min_avg_load = avg_load; + if (load < min_load) { + min_load = load; idlest = group; } @@ -5668,18 +5646,10 @@ find_idlest_group(struct sched_domain *sd, struct task_struct *p, * local domain to be very lightly loaded relative to the remote * domains but "imbalance" skews the comparison making remote CPUs * look much more favourable. When considering cross-domain, add - * imbalance to the runnable load on the remote node and consider - * staying local. + * imbalance to the load on the remote node and consider staying + * local. */ - if ((sd->flags & SD_NUMA) && - min_runnable_load + imbalance >= this_runnable_load) - return NULL; - - if (min_runnable_load > (this_runnable_load + imbalance)) - return NULL; - - if ((this_runnable_load < (min_runnable_load + imbalance)) && - (100*this_avg_load < imbalance_scale*min_avg_load)) + if (min_load + imbalance >= this_load) return NULL; return idlest; -- 2.7.4