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=-2.3 required=3.0 tests=HEADER_FROM_DIFFERENT_DOMAINS, MAILING_LIST_MULTI,SPF_PASS,USER_AGENT_MUTT 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 033DCC4321E for ; Fri, 7 Sep 2018 12:37:45 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id A1D8220844 for ; Fri, 7 Sep 2018 12:37:45 +0000 (UTC) DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org A1D8220844 Authentication-Results: mail.kernel.org; dmarc=none (p=none dis=none) header.from=techsingularity.net Authentication-Results: mail.kernel.org; spf=none smtp.mailfrom=linux-kernel-owner@vger.kernel.org Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1729198AbeIGRS2 (ORCPT ); Fri, 7 Sep 2018 13:18:28 -0400 Received: from outbound-smtp08.blacknight.com ([46.22.139.13]:35692 "EHLO outbound-smtp08.blacknight.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1728103AbeIGRS2 (ORCPT ); Fri, 7 Sep 2018 13:18:28 -0400 Received: from mail.blacknight.com (pemlinmail04.blacknight.ie [81.17.254.17]) by outbound-smtp08.blacknight.com (Postfix) with ESMTPS id 736941C2BD2 for ; Fri, 7 Sep 2018 13:37:41 +0100 (IST) Received: (qmail 31412 invoked from network); 7 Sep 2018 12:37:41 -0000 Received: from unknown (HELO techsingularity.net) (mgorman@techsingularity.net@[37.228.229.88]) by 81.17.254.9 with ESMTPSA (AES256-SHA encrypted, authenticated); 7 Sep 2018 12:37:41 -0000 Date: Fri, 7 Sep 2018 13:37:39 +0100 From: Mel Gorman To: Peter Zijlstra Cc: Srikar Dronamraju , Ingo Molnar , Rik van Riel , LKML Subject: Re: [PATCH 4/4] sched/numa: Do not move imbalanced load purely on the basis of an idle CPU Message-ID: <20180907123739.GE1719@techsingularity.net> References: <20180907101139.20760-1-mgorman@techsingularity.net> <20180907101139.20760-5-mgorman@techsingularity.net> <20180907113309.GU24106@hirez.programming.kicks-ass.net> MIME-Version: 1.0 Content-Type: text/plain; charset=iso-8859-15 Content-Disposition: inline In-Reply-To: <20180907113309.GU24106@hirez.programming.kicks-ass.net> 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, Sep 07, 2018 at 01:33:09PM +0200, Peter Zijlstra wrote: > > --- > > 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 d59d3e00a480..d4c289c11012 100644 > > --- a/kernel/sched/fair.c > > +++ b/kernel/sched/fair.c > > @@ -1560,7 +1560,7 @@ static bool task_numa_compare(struct task_numa_env *env, > > goto unlock; > > > > if (!cur) { > > - if (maymove || imp > env->best_imp) > > + if (maymove) > > goto assign; > > else > > goto unlock; > > Srikar's patch here: > > http://lkml.kernel.org/r/1533276841-16341-4-git-send-email-srikar@linux.vnet.ibm.com > > Also frobs this condition, but in a less radical way. Does that yield > similar results? I can check. I do wonder of course if the less radical approach just means that automatic NUMA balancing and the load balancer simply disagree about placement at a different time. It'll take a few days to have an answer as the battery of workloads to check this take ages. -- Mel Gorman SUSE Labs