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=-5.1 required=3.0 tests=DKIM_INVALID,DKIM_SIGNED, HEADER_FROM_DIFFERENT_DOMAINS,MAILING_LIST_MULTI,SIGNED_OFF_BY,SPF_HELO_NONE, SPF_PASS,USER_AGENT_SANE_1 autolearn=ham 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 2FC9AC33CB1 for ; Fri, 17 Jan 2020 15:11:56 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id 0527B2072E for ; Fri, 17 Jan 2020 15:11:56 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=fail reason="signature verification failed" (2048-bit key) header.d=infradead.org header.i=@infradead.org header.b="RSMVzOWH" Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1729158AbgAQPLy (ORCPT ); Fri, 17 Jan 2020 10:11:54 -0500 Received: from bombadil.infradead.org ([198.137.202.133]:34568 "EHLO bombadil.infradead.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1729140AbgAQPLx (ORCPT ); Fri, 17 Jan 2020 10:11:53 -0500 DKIM-Signature: v=1; a=rsa-sha256; q=dns/txt; c=relaxed/relaxed; d=infradead.org; s=bombadil.20170209; h=In-Reply-To:Content-Type:MIME-Version :References:Message-ID:Subject:Cc:To:From:Date:Sender:Reply-To: Content-Transfer-Encoding:Content-ID:Content-Description:Resent-Date: Resent-From:Resent-Sender:Resent-To:Resent-Cc:Resent-Message-ID:List-Id: List-Help:List-Unsubscribe:List-Subscribe:List-Post:List-Owner:List-Archive; bh=6XkN9OOxlWNG+NnNqQFZrrwnqRAB2I/Nrd6IFwG7+RY=; b=RSMVzOWHXhbXk5ybQd1Ac8U8n mr0pOzNXDL8GNif+bLGGz7kTu4dfR9Y1ATuXasz97lbZ1uSNU6Q58wCj9hxLDKAuMt2FE0HikFYZG yyGJwwGolFaHsIqxQOF7T2DRetuhzhzVGLPxzN6E8XC/2Oyy8RiIf8AiH90jcTM5ZXFUUaV9KpiM/ Ua1abFQGKzfocrNi/931/DqM8YWzhPVSZh6QsfT6FaaW5JP44iTAfBwj0eV1UURyCU/CbQ7uJFDLC QyNDoFvCbEAAkPyfLJghZPnoXNvSz+LOsiKqvwObJHceNoJbQgkY7sykpk8cmUEh8TR/jvPQgPRmi I0q0iEddQ==; Received: from j217100.upc-j.chello.nl ([24.132.217.100] helo=noisy.programming.kicks-ass.net) by bombadil.infradead.org with esmtpsa (Exim 4.92.3 #3 (Red Hat Linux)) id 1isTHZ-0006sX-K9; Fri, 17 Jan 2020 15:11:33 +0000 Received: from hirez.programming.kicks-ass.net (hirez.programming.kicks-ass.net [192.168.1.225]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (Client did not present a certificate) by noisy.programming.kicks-ass.net (Postfix) with ESMTPS id 143B3300F4B; Fri, 17 Jan 2020 16:09:54 +0100 (CET) Received: by hirez.programming.kicks-ass.net (Postfix, from userid 1000) id 492602020D8FC; Fri, 17 Jan 2020 16:11:31 +0100 (CET) Date: Fri, 17 Jan 2020 16:11:31 +0100 From: Peter Zijlstra To: Vincent Guittot Cc: Mel Gorman , Phil Auld , Ingo Molnar , Valentin Schneider , Srikar Dronamraju , Quentin Perret , Dietmar Eggemann , Morten Rasmussen , Hillf Danton , Parth Shah , Rik van Riel , LKML Subject: Re: [PATCH] sched, fair: Allow a small load imbalance between low utilisation SD_NUMA domains v4 Message-ID: <20200117151131.GG14879@hirez.programming.kicks-ass.net> References: <20200114101319.GO3466@techsingularity.net> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: User-Agent: Mutt/1.10.1 (2018-07-13) Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Fri, Jan 17, 2020 at 04:09:33PM +0100, Vincent Guittot wrote: > On Tue, 14 Jan 2020 at 11:13, Mel Gorman wrote: > > In general, the patch simply seeks to avoid unnecessary cross-node > > migrations in the basic case where imbalances are very small. For low > > utilisation communicating workloads, this patch generally behaves better > > with less NUMA balancing activity. For high utilisation, there is no > > change in behaviour. > > > > Signed-off-by: Mel Gorman > > Reviewed-by: Vincent Guittot Thanks all!