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 Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by smtp.lore.kernel.org (Postfix) with ESMTP id CE660C433FE for ; Thu, 14 Apr 2022 09:29:52 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S241806AbiDNJcO (ORCPT ); Thu, 14 Apr 2022 05:32:14 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:58506 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S241807AbiDNJcC (ORCPT ); Thu, 14 Apr 2022 05:32:02 -0400 Received: from mailgw02.mediatek.com (unknown [210.61.82.184]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id AAE7D64CD for ; Thu, 14 Apr 2022 02:29:34 -0700 (PDT) X-UUID: a1734ec1a9c849708e20aea0a5f7ee0e-20220414 X-UUID: a1734ec1a9c849708e20aea0a5f7ee0e-20220414 Received: from mtkcas11.mediatek.inc [(172.21.101.40)] by mailgw02.mediatek.com (envelope-from ) (Generic MTA with TLSv1.2 ECDHE-RSA-AES256-SHA384 256/256) with ESMTP id 1359392002; Thu, 14 Apr 2022 17:29:29 +0800 Received: from mtkcas11.mediatek.inc (172.21.101.40) by mtkmbs10n2.mediatek.inc (172.21.101.183) with Microsoft SMTP Server (version=TLS1_2, cipher=TLS_ECDHE_RSA_WITH_AES_256_CBC_SHA384) id 15.2.792.3; Thu, 14 Apr 2022 17:29:29 +0800 Received: from mtksdccf07 (172.21.84.99) by mtkcas11.mediatek.inc (172.21.101.73) with Microsoft SMTP Server id 15.0.1497.2 via Frontend Transport; Thu, 14 Apr 2022 17:29:28 +0800 Message-ID: Subject: Re: [PATCH 1/1] [PATCH v2]sched/pelt: Refine the enqueue_load_avg calculate method From: Kuyo Chang To: Dietmar Eggemann , Ingo Molnar , Peter Zijlstra , Juri Lelli , Vincent Guittot , Steven Rostedt , Ben Segall , "Mel Gorman" , Daniel Bristot de Oliveira , Matthias Brugger CC: , , , Date: Thu, 14 Apr 2022 17:29:28 +0800 In-Reply-To: References: <20220414015940.9537-1-kuyo.chang@mediatek.com> Content-Type: text/plain; charset="UTF-8" X-Mailer: Evolution 3.28.5-0ubuntu0.18.04.2 MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-MTK: N Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Thu, 2022-04-14 at 11:02 +0200, Dietmar Eggemann wrote: > On 14/04/2022 03:59, Kuyo Chang wrote: > > From: kuyo chang > > [...] > > > diff --git a/kernel/sched/fair.c b/kernel/sched/fair.c > > index d4bd299d67ab..159274482c4e 100644 > > --- a/kernel/sched/fair.c > > +++ b/kernel/sched/fair.c > > @@ -3829,10 +3829,12 @@ static void attach_entity_load_avg(struct > > cfs_rq *cfs_rq, struct sched_entity *s > > > > se->avg.runnable_sum = se->avg.runnable_avg * divider; > > > > - se->avg.load_sum = divider; > > - if (se_weight(se)) { > > + se->avg.load_sum = se->avg.load_avg * divider; > > + if (se_weight(se) < se->avg.load_sum) { > > se->avg.load_sum = > > - div_u64(se->avg.load_avg * se->avg.load_sum, > > se_weight(se)); > > + div_u64(se->avg.load_sum, se_weight(se)); > > Seems that this will fit on one line now. No braces needed then. Thanks for your friendly reminder. > > > + } else { > > + se->avg.load_sum = 1; > > } > > > > enqueue_load_avg(cfs_rq, se); > > Looks like taskgroups are not affected since they get always online > with cpu.shares/weight = 1024 (cgroup v1): > > cpu_cgroup_css_online() -> online_fair_sched_group() -> > attach_entity_cfs_rq() -> attach_entity_load_avg() > > And reweight_entity() does not have this issue. > > Tested with `qemu-system-x86_64 ... cores=64 ... -enable-kvm` and > weight=88761 for nice=0 tasks plus forcing se->avg.load_avg = 1 > before > the div_u64() in attach_entity_load_avg(). > > Tested-by: Dietmar Eggemann