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=-19.4 required=3.0 tests=BAYES_00,DKIMWL_WL_HIGH, DKIM_SIGNED,DKIM_VALID,DKIM_VALID_AU,HEADER_FROM_DIFFERENT_DOMAINS, INCLUDES_CR_TRAILER,INCLUDES_PATCH,MAILING_LIST_MULTI,SPF_HELO_NONE,SPF_PASS, 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 815E2C2B9F6 for ; Mon, 10 May 2021 11:20:40 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 75DDB6101E for ; Mon, 10 May 2021 11:20:40 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S237968AbhEJLQh (ORCPT ); Mon, 10 May 2021 07:16:37 -0400 Received: from mail.kernel.org ([198.145.29.99]:41710 "EHLO mail.kernel.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S231736AbhEJKwI (ORCPT ); Mon, 10 May 2021 06:52:08 -0400 Received: by mail.kernel.org (Postfix) with ESMTPSA id AC32C61961; Mon, 10 May 2021 10:40:48 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=linuxfoundation.org; s=korg; t=1620643249; bh=wulewUnb/jPqQ3O6/IZe+6GoO25VtwJfJi1sGBbkcSc=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=zfPuKnp/JFrK6f32rO8clUbwoB7LE6uFPAZj7zw+8Ps6yLzjN1/43Xlw1wd7vJjTF D0IhV0yIXsq9vOJIKoHjECIaT6zth9aRzaLBpZXsGR9qrhinYmBqLPqHLinDa4xaq4 zaClW58etwYjtU4dHA0H5nlxzFJ0ZYXlTsKeJ9Uo= From: Greg Kroah-Hartman To: linux-kernel@vger.kernel.org Cc: Greg Kroah-Hartman , stable@vger.kernel.org, "Peter Zijlstra (Intel)" , Valentin Schneider , Sasha Levin Subject: [PATCH 5.10 204/299] sched,fair: Alternative sched_slice() Date: Mon, 10 May 2021 12:20:01 +0200 Message-Id: <20210510102011.679790795@linuxfoundation.org> X-Mailer: git-send-email 2.31.1 In-Reply-To: <20210510102004.821838356@linuxfoundation.org> References: <20210510102004.821838356@linuxfoundation.org> User-Agent: quilt/0.66 MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org From: Peter Zijlstra [ Upstream commit 0c2de3f054a59f15e01804b75a04355c48de628c ] The current sched_slice() seems to have issues; there's two possible things that could be improved: - the 'nr_running' used for __sched_period() is daft when cgroups are considered. Using the RQ wide h_nr_running seems like a much more consistent number. - (esp) cgroups can slice it real fine, which makes for easy over-scheduling, ensure min_gran is what the name says. Signed-off-by: Peter Zijlstra (Intel) Tested-by: Valentin Schneider Link: https://lkml.kernel.org/r/20210412102001.611897312@infradead.org Signed-off-by: Sasha Levin --- kernel/sched/fair.c | 12 +++++++++++- kernel/sched/features.h | 3 +++ 2 files changed, 14 insertions(+), 1 deletion(-) diff --git a/kernel/sched/fair.c b/kernel/sched/fair.c index 481f4cc0958f..a0239649c741 100644 --- a/kernel/sched/fair.c +++ b/kernel/sched/fair.c @@ -700,7 +700,13 @@ static u64 __sched_period(unsigned long nr_running) */ static u64 sched_slice(struct cfs_rq *cfs_rq, struct sched_entity *se) { - u64 slice = __sched_period(cfs_rq->nr_running + !se->on_rq); + unsigned int nr_running = cfs_rq->nr_running; + u64 slice; + + if (sched_feat(ALT_PERIOD)) + nr_running = rq_of(cfs_rq)->cfs.h_nr_running; + + slice = __sched_period(nr_running + !se->on_rq); for_each_sched_entity(se) { struct load_weight *load; @@ -717,6 +723,10 @@ static u64 sched_slice(struct cfs_rq *cfs_rq, struct sched_entity *se) } slice = __calc_delta(slice, se->load.weight, load); } + + if (sched_feat(BASE_SLICE)) + slice = max(slice, (u64)sysctl_sched_min_granularity); + return slice; } diff --git a/kernel/sched/features.h b/kernel/sched/features.h index 68d369cba9e4..f1bf5e12d889 100644 --- a/kernel/sched/features.h +++ b/kernel/sched/features.h @@ -90,3 +90,6 @@ SCHED_FEAT(WA_BIAS, true) */ SCHED_FEAT(UTIL_EST, true) SCHED_FEAT(UTIL_EST_FASTUP, true) + +SCHED_FEAT(ALT_PERIOD, true) +SCHED_FEAT(BASE_SLICE, true) -- 2.30.2