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_HELO_NONE,SPF_PASS,USER_AGENT_SANE_1 autolearn=no 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 B1A88C34021 for ; Mon, 17 Feb 2020 15:31:11 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id 91A272070B for ; Mon, 17 Feb 2020 15:31:11 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1728774AbgBQPbK (ORCPT ); Mon, 17 Feb 2020 10:31:10 -0500 Received: from outbound-smtp33.blacknight.com ([81.17.249.66]:35716 "EHLO outbound-smtp33.blacknight.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1726528AbgBQPbK (ORCPT ); Mon, 17 Feb 2020 10:31:10 -0500 Received: from mail.blacknight.com (unknown [81.17.254.10]) by outbound-smtp33.blacknight.com (Postfix) with ESMTPS id 76BEFD038A for ; Mon, 17 Feb 2020 15:31:08 +0000 (GMT) Received: (qmail 8451 invoked from network); 17 Feb 2020 15:31:08 -0000 Received: from unknown (HELO techsingularity.net) (mgorman@techsingularity.net@[84.203.18.57]) by 81.17.254.9 with ESMTPSA (AES256-SHA encrypted, authenticated); 17 Feb 2020 15:31:08 -0000 Date: Mon, 17 Feb 2020 15:31:06 +0000 From: Mel Gorman To: Peter Zijlstra Cc: Vincent Guittot , Ingo Molnar , Juri Lelli , Dietmar Eggemann , Steven Rostedt , Ben Segall , Valentin Schneider , Phil Auld , Hillf Danton , LKML Subject: Re: [PATCH 00/13] Reconcile NUMA balancing decisions with the load balancer v3 Message-ID: <20200217153106.GL3466@techsingularity.net> References: <20200217104402.11643-1-mgorman@techsingularity.net> <20200217145216.GR14897@hirez.programming.kicks-ass.net> MIME-Version: 1.0 Content-Type: text/plain; charset=iso-8859-15 Content-Disposition: inline In-Reply-To: <20200217145216.GR14897@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 Mon, Feb 17, 2020 at 03:52:16PM +0100, Peter Zijlstra wrote: > On Mon, Feb 17, 2020 at 02:49:11PM +0100, Vincent Guittot wrote: > > > Patches 4-5 are Vincent's and use very similar code patterns and logic > > > between NUMA and load balancer. Patch 6 is a fix to Vincent's work that > > > is necessary to avoid serious imbalances being introduced by the NUMA > > > > Yes the test added in load_too_imbalanced() by patch 5 doesn't seem to > > be a good choice. > > I haven't remove it as it was done by your patch 6 but it might worth > > removing it directly if a new version is needed > > Aside of that, Vincent's patches look good to me. Fully agreed, I think it's now much easier to understand the two balancers when put side by side in addition to getting some performance gains. Even if a regression is found, I think it'll be due to a workload seeing an advantage when NUMA balancer constantly overrides the load balancer. If that happens, the imbalance can be governed by adjust_numa_balance so that the two balancers avoid fighting each other again. -- Mel Gorman SUSE Labs