From patchwork Tue Aug 7 15:56:25 2018 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Vincent Guittot X-Patchwork-Id: 143590 Delivered-To: patch@linaro.org Received: by 2002:a2e:9754:0:0:0:0:0 with SMTP id f20-v6csp4668646ljj; Tue, 7 Aug 2018 08:56:40 -0700 (PDT) X-Google-Smtp-Source: AAOMgpeKL9WU9wdewbaHb01nRhFS3o6fzfYeICNYxFB14YARnQcA6U133b3TY1BxLjsfHeich2vU X-Received: by 2002:a62:cc4d:: with SMTP id a74-v6mr22583376pfg.200.1533657400692; Tue, 07 Aug 2018 08:56:40 -0700 (PDT) ARC-Seal: i=1; a=rsa-sha256; t=1533657400; cv=none; d=google.com; s=arc-20160816; b=U7AmabjSU+TRQrSJ29sdkbtuAWGe/XxDa4s/SiLqzFoSzsLcHMqizvjPkS1fxEiUNV wvJudYKgxPAlSpGIOA35OCQclo3RaUhMXlv4RUCx697Dw/23jo7Gc6q+a/cRb51cRnTH FwzdsbNdtNkJUwxYxcE5nqqifNvJYcWp+twiwWtK7IE+BnSqxpofc7tdm04LMRZazCyX 0LihYRRPPj8eKLYpFC41vcAGCVJ0Wj/xFPFeFT7d5nqve3dGFqMosTWlSlfisSZ6O4ML 8Vw2SserIp5X/f2gXdT8omgPXLTNtvW1+OakkdixVI8MvyKbYZWaEO0aQ/Yg4mjuwMOu eqtQ== ARC-Message-Signature: i=1; a=rsa-sha256; c=relaxed/relaxed; d=google.com; s=arc-20160816; h=list-id:precedence:sender:references:in-reply-to:message-id:date :subject:cc:to:from:dkim-signature:arc-authentication-results; bh=dwnEuOfvwkhUPwkhLMArV3ygXldRpqW8K54UcT0yLyM=; b=aJ1bYhQfNhJdUUyNvWwwG3pqtcmgLQMr5X/zEKOJ8n7J1L3vTKQq3P5+FGq4/Yp8zd ktqqADjR2UY8DzFo1jmg/N0Qn+Crnf8JgnYwq/VqpzymNkMyiombb/0XfEz7PNIi9gqw zi69Qtj/Y8CMVXHylnHgVVZf69Iu1xbXmsVkN7Fp+MMo9wigI0L4q6ITna0dZhYcMY+g 4AcxmP7TdyhJp8i4FhRCHnhVZCHcmMqI8bQuVIFrLOJEv5bEKPlz6Q1NzrHLMdMZBAhv J0ZNldhBFKFZKZfrvIY38aOWOGG/e3rNGZRcaEgQ4bQJLEKyXHLPpbcEektTDTLLfGPA 7eXw== ARC-Authentication-Results: i=1; mx.google.com; dkim=pass header.i=@linaro.org header.s=google header.b=JVUMaxLV; 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 Return-Path: Received: from vger.kernel.org (vger.kernel.org. [209.132.180.67]) by mx.google.com with ESMTP id n3-v6si1685020pga.298.2018.08.07.08.56.40; Tue, 07 Aug 2018 08:56:40 -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=JVUMaxLV; 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 S2390023AbeHGSLd (ORCPT + 31 others); Tue, 7 Aug 2018 14:11:33 -0400 Received: from mail-wr1-f67.google.com ([209.85.221.67]:46218 "EHLO mail-wr1-f67.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S2388481AbeHGSLc (ORCPT ); Tue, 7 Aug 2018 14:11:32 -0400 Received: by mail-wr1-f67.google.com with SMTP id h14-v6so16230385wrw.13 for ; Tue, 07 Aug 2018 08:56:35 -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=dwnEuOfvwkhUPwkhLMArV3ygXldRpqW8K54UcT0yLyM=; b=JVUMaxLVKtdy9L0fArqR+35obj9iXp7E7CdS9ozqBjeFJxQOjxwc9cHSmLAvR9Rjwo fiEO7XmM22XiDcweeGF6JP9zyDBIXQMM/5kkH2KzGr/bHAF8/EMYiAvGZSrLVYDj8RsB 1XRiHElueUJmIBPBUm8eZKbpp5nsFBy/IQwZk= 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=dwnEuOfvwkhUPwkhLMArV3ygXldRpqW8K54UcT0yLyM=; b=Xp3ZJrM6Oe7UQ6oyi323XYW9Z0EPjsMyEA+eUOBZOlfnzaQVW/BljwYDudNMAZC//W 46EQi6LT5YhMpy2yxuqq8SbWPkhw3DUQJRkAvo5wbEieMfFJxWES1AEQylJ9zBZxYvNU BEEmDy5we+Xyr/JlsSZuTfLgO+1Ni13fD3TtpulIPzhMWUA+uJS2iJz7QH7qfjReaeOD OL1vpeE9iowRJkOAAxksOrtG5ub+0RifsGEOPZTea30PGrne+iuA/cxvlfPkQLRhkIdB IlyX36x9iobBBT4chGITY+mF/+1gl47O+XxBVf0zvoE07aLddwhQVGxsPwLAlg4Mn9bQ YHsg== X-Gm-Message-State: AOUpUlGvnVKRL4tC9jYVY/hwusp6Ue56W/RCJjft9yxGpWB1uCOo9Q0j ii9pmwcoyqNvCWNdCYwE3cfLqw== X-Received: by 2002:adf:8b1e:: with SMTP id n30-v6mr5019651wra.282.1533657394648; Tue, 07 Aug 2018 08:56:34 -0700 (PDT) Received: from localhost.localdomain ([2a01:e0a:f:6020:41ad:95bb:4cb8:621f]) by smtp.gmail.com with ESMTPSA id y203-v6sm2903644wmd.1.2018.08.07.08.56.33 (version=TLS1_2 cipher=ECDHE-RSA-AES128-SHA bits=128/128); Tue, 07 Aug 2018 08:56:33 -0700 (PDT) From: Vincent Guittot To: peterz@infradead.org, mingo@kernel.org, linux-kernel@vger.kernel.org Cc: valentin.schneider@arm.com, Morten.Rasmussen@arm.com, Vincent Guittot Subject: [PATCH 1/3] sched/fair: fix rounding issue for asym packing Date: Tue, 7 Aug 2018 17:56:25 +0200 Message-Id: <1533657387-29039-2-git-send-email-vincent.guittot@linaro.org> X-Mailer: git-send-email 2.7.4 In-Reply-To: <1533657387-29039-1-git-send-email-vincent.guittot@linaro.org> References: <1533657387-29039-1-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 When check_asym_packing() is triggered, the imbalance is set to : busiest_stat.avg_load * busiest_stat.group_capacity / SCHED_CAPACITY_SCALE busiest_stat.avg_load also comes from a division and the final rounding can make imbalance slightly lower than the weighted load of the cfs_rq. But this is enough to skip the rq in find_busiest_queue and prevents asym migration to happen. Add 1 to the avg_load to make sure that the targeted cpu will not be skipped unexpectidly. Signed-off-by: Vincent Guittot --- kernel/sched/fair.c | 6 ++++++ 1 file changed, 6 insertions(+) -- 2.7.4 diff --git a/kernel/sched/fair.c b/kernel/sched/fair.c index 309c93f..c376cd0 100644 --- a/kernel/sched/fair.c +++ b/kernel/sched/fair.c @@ -7780,6 +7780,12 @@ static inline void update_sg_lb_stats(struct lb_env *env, /* Adjust by relative CPU capacity of the group */ sgs->group_capacity = group->sgc->capacity; sgs->avg_load = (sgs->group_load*SCHED_CAPACITY_SCALE) / sgs->group_capacity; + /* + * Prevent division rounding to make the computation of imbalance + * slightly less than original value and to prevent the rq to be then + * selected as busiest queue + */ + sgs->avg_load += 1; if (sgs->sum_nr_running) sgs->load_per_task = sgs->sum_weighted_load / sgs->sum_nr_running;