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 mail.kernel.org (mail.kernel.org [198.145.29.99]) by smtp.lore.kernel.org (Postfix) with ESMTP id EA7F1C433F5 for ; Tue, 28 Sep 2021 12:24:31 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id D104B6101E for ; Tue, 28 Sep 2021 12:24:31 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S240607AbhI1M0J (ORCPT ); Tue, 28 Sep 2021 08:26:09 -0400 Received: from Galois.linutronix.de ([193.142.43.55]:35316 "EHLO galois.linutronix.de" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S240528AbhI1M0G (ORCPT ); Tue, 28 Sep 2021 08:26:06 -0400 Message-ID: <20210928122411.425097596@linutronix.de> DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=linutronix.de; s=2020; t=1632831866; h=from:from:reply-to:subject:subject:date:date:message-id:message-id: to:to:cc:cc:mime-version:mime-version:content-type:content-type: references:references; bh=i59qocCoGCnBtQVrBi2XUTcWPiODGidnjCAobrgCY6U=; b=qbtlVxewaGzD6eve/blPDdhZl2Y4Peiwk9pLd+6clvjH17E7MRisZtQEK+Wgjnhf3IyJuF SnEMc0RG06mEv2fmN87eQ+QTN8R2WJmwFasiyrzUWBwAPxXjHyX1zvynp2EjaMrNHxabSb TFuxDpdJa79/p8PhObMkF7rOSC96xRoS0a965umh453um6mHk1eGHJHfHlqd8ZEBjnFUPk p+/A/1wTnpgJcb/85DgxSIh3JY4qn6T6bm51swacr07Q8Mz4qee49mISUrPtubfO3Vwv2c GuKICBMYgpvfQ+F0IOJDe/tT46WuAW4Pv47Q1iX3567wV2XVnMtN8OgK1mguMQ== DKIM-Signature: v=1; a=ed25519-sha256; c=relaxed/relaxed; d=linutronix.de; s=2020e; t=1632831866; h=from:from:reply-to:subject:subject:date:date:message-id:message-id: to:to:cc:cc:mime-version:mime-version:content-type:content-type: references:references; bh=i59qocCoGCnBtQVrBi2XUTcWPiODGidnjCAobrgCY6U=; b=1EYbUtAw7h1W4Rb7aeMPirUSbqjX0CVkN+pYkdaBskglmU7tXz85UhIB8K7W4VX1bdhWeA oPn7MBAfHq4a5aBg== From: Thomas Gleixner To: LKML Cc: Peter Zijlstra , Ingo Molnar , Masami Hiramatsu , Sebastian Andrzej Siewior Subject: [patch 1/5] sched: Limit the number of task migrations per batch on RT References: <20210928122339.502270600@linutronix.de> MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Date: Tue, 28 Sep 2021 14:24:25 +0200 (CEST) Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Batched task migrations are a source for large latencies as they keep the scheduler from running while processing the migrations. Limit the batch size to 8 instead of 32 when running on a RT enabled kernel. Signed-off-by: Thomas Gleixner --- kernel/sched/core.c | 4 ++++ 1 file changed, 4 insertions(+) --- --- a/kernel/sched/core.c +++ b/kernel/sched/core.c @@ -74,7 +74,11 @@ const_debug unsigned int sysctl_sched_fe * Number of tasks to iterate in a single balance run. * Limited because this is done with IRQs disabled. */ +#ifdef CONFIG_PREEMPT_RT +const_debug unsigned int sysctl_sched_nr_migrate = 8; +#else const_debug unsigned int sysctl_sched_nr_migrate = 32; +#endif /* * period over which we measure -rt task CPU usage in us.