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=-10.1 required=3.0 tests=DKIMWL_WL_HIGH,DKIM_SIGNED, DKIM_VALID,DKIM_VALID_AU,INCLUDES_PATCH,MAILING_LIST_MULTI,SIGNED_OFF_BY, SPF_HELO_NONE,SPF_PASS,URIBL_BLOCKED,USER_AGENT_GIT autolearn=unavailable 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 AC0B6C433DF for ; Mon, 29 Jun 2020 22:06:01 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 83DD720780 for ; Mon, 29 Jun 2020 22:06:01 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=default; t=1593468361; bh=ez/Xza8UAdQdL+cOs3YfVkwIynKjFgX2omR/0GaZb1Y=; h=From:To:Cc:Subject:Date:In-Reply-To:References:List-ID:From; b=J6dIeiaESM4rIA6jZLM4FnYQYprWNITgBb5WPosHI2Xwof9OwsYCVjbOcVWOcUXXi BNNJm0/sCimiGdsh7etDSrZh4PEr1hSjDuyiBkZMngavLyYOmxgDTRGU0nw0yM5CS0 5vlqSMifHpvjYe8FYEQC49EP+vl8mVXEKI/EtlY0= Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S2404739AbgF2WFt (ORCPT ); Mon, 29 Jun 2020 18:05:49 -0400 Received: from mail.kernel.org ([198.145.29.99]:56794 "EHLO mail.kernel.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1726148AbgF2SfT (ORCPT ); Mon, 29 Jun 2020 14:35:19 -0400 Received: from sasha-vm.mshome.net (c-73-47-72-35.hsd1.nh.comcast.net [73.47.72.35]) (using TLSv1.2 with cipher ECDHE-RSA-AES128-GCM-SHA256 (128/128 bits)) (No client certificate requested) by mail.kernel.org (Postfix) with ESMTPSA id 1C5AF24757; Mon, 29 Jun 2020 15:21:12 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=default; t=1593444072; bh=ez/Xza8UAdQdL+cOs3YfVkwIynKjFgX2omR/0GaZb1Y=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=AUWMbIW/UDbfVVPtABk1o0h2ntRkuehxdxEs+2ao8/uOlGI8BC2vEt8Tr8WTCTdk1 lw+/llLhLVRWKc7gVGZZWj6heq0Wy9Q8NMH+JhOO3ts7ZgIamvZMNMGL0kg8WDXbye JaXZv32ZEoYfkHKyb9xvaL5cxqe+6rjJMHZ/zOXg= From: Sasha Levin To: linux-kernel@vger.kernel.org, stable@vger.kernel.org Cc: Vincent Guittot , kernel test robot , Peter Zijlstra , Sasha Levin Subject: [PATCH 5.7 181/265] sched/cfs: change initial value of runnable_avg Date: Mon, 29 Jun 2020 11:16:54 -0400 Message-Id: <20200629151818.2493727-182-sashal@kernel.org> X-Mailer: git-send-email 2.25.1 In-Reply-To: <20200629151818.2493727-1-sashal@kernel.org> References: <20200629151818.2493727-1-sashal@kernel.org> MIME-Version: 1.0 X-KernelTest-Patch: http://kernel.org/pub/linux/kernel/v5.x/stable-review/patch-5.7.7-rc1.gz X-KernelTest-Tree: git://git.kernel.org/pub/scm/linux/kernel/git/stable/linux-stable-rc.git X-KernelTest-Branch: linux-5.7.y X-KernelTest-Patches: git://git.kernel.org/pub/scm/linux/kernel/git/stable/stable-queue.git X-KernelTest-Version: 5.7.7-rc1 X-KernelTest-Deadline: 2020-07-01T15:14+00:00 X-stable: review X-Patchwork-Hint: Ignore Content-Transfer-Encoding: 8bit Sender: stable-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: stable@vger.kernel.org From: Vincent Guittot [ Upstream commit e21cf43406a190adfcc4bfe592768066fb3aaa9b ] Some performance regression on reaim benchmark have been raised with commit 070f5e860ee2 ("sched/fair: Take into account runnable_avg to classify group") The problem comes from the init value of runnable_avg which is initialized with max value. This can be a problem if the newly forked task is finally a short task because the group of CPUs is wrongly set to overloaded and tasks are pulled less agressively. Set initial value of runnable_avg equals to util_avg to reflect that there is no waiting time so far. Fixes: 070f5e860ee2 ("sched/fair: Take into account runnable_avg to classify group") Reported-by: kernel test robot Signed-off-by: Vincent Guittot Signed-off-by: Peter Zijlstra (Intel) Link: https://lkml.kernel.org/r/20200624154422.29166-1-vincent.guittot@linaro.org Signed-off-by: Sasha Levin --- kernel/sched/fair.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) diff --git a/kernel/sched/fair.c b/kernel/sched/fair.c index 2ae7e30ccb33c..5725199b32dcf 100644 --- a/kernel/sched/fair.c +++ b/kernel/sched/fair.c @@ -807,7 +807,7 @@ void post_init_entity_util_avg(struct task_struct *p) } } - sa->runnable_avg = cpu_scale; + sa->runnable_avg = sa->util_avg; if (p->sched_class != &fair_sched_class) { /* -- 2.25.1