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=-0.8 required=3.0 tests=DKIM_SIGNED,DKIM_VALID, DKIM_VALID_AU,HEADER_FROM_DIFFERENT_DOMAINS,MAILING_LIST_MULTI,SPF_HELO_NONE, SPF_PASS,URIBL_BLOCKED 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 0F0D4C2BA83 for ; Thu, 13 Feb 2020 17:15:38 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id D8935206DB for ; Thu, 13 Feb 2020 17:15:37 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=pass (2048-bit key) header.d=linaro.org header.i=@linaro.org header.b="obj7tBtr" Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1728113AbgBMRPh (ORCPT ); Thu, 13 Feb 2020 12:15:37 -0500 Received: from mail-lj1-f170.google.com ([209.85.208.170]:42465 "EHLO mail-lj1-f170.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1727781AbgBMRPg (ORCPT ); Thu, 13 Feb 2020 12:15:36 -0500 Received: by mail-lj1-f170.google.com with SMTP id d10so7493245ljl.9 for ; Thu, 13 Feb 2020 09:15:35 -0800 (PST) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=linaro.org; s=google; h=mime-version:references:in-reply-to:from:date:message-id:subject:to :cc; bh=/ZgnOA2RdYtHkbQdDxZ4YJyDdLwvDtzxs2Sj136XFtk=; b=obj7tBtrmvKlOHKhtyTYC09hT6nbkdjmpEN7XYnGuuciKphxb5wkIxq/x7JAWuvnq9 wRl9dDJQ+RIyfFTd1pXN4zIkwraBNbYiW7Y6X6h8ZZtkBhfTp95iktaVQrvtsHuy66yT Nn7kezc+1iYATMKNa2V03UcGN++jZcVYi0onzJERai/ahzUOaHpepbC7mTJkPzQOXvxL EL9KZZ75ud6DO9s8+U+8ZOTVvxmM+fXyDXkh+/lg9LgyUqpYd0pSaLIQRnxdb0eXy3lo yNb7BpKysQYP5KwCrFAXqbCs9s3GbfCCk+OLQXpbmoUawKXSER39co0gZNhED13sKljt rzRQ== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20161025; h=x-gm-message-state:mime-version:references:in-reply-to:from:date :message-id:subject:to:cc; bh=/ZgnOA2RdYtHkbQdDxZ4YJyDdLwvDtzxs2Sj136XFtk=; b=unNw06PKZ8TIqhXKAIYqDhSG3lHDBIvsmtQA1Kw3cPn6pHQSPdENnliZUqdWV6hMPe DjZAXuIVlFBsUdyZcsodS0yKiiBXaVnYDkiLV6W3hIagqeuLctJZ5dT9xYSCpnc1dNqU xh7fgyGp88ZMzkat2pOclFe61oyuiL6lcLezOMwFQQiiwmrT8A9HMdNC6f9DI5GituWA eZ8NnaKCLllxbCD1v/wcPiTvnjq+U1e/mmsJcoQagZF9nwoBAoq0/EWqnPahBsZZTgQF GeyBbv4MOHIL6VRs1/DXR1QqjuPxKY02HOffk6qshxtUREyyqWWpbqMivGz14oIz+v/1 Wshg== X-Gm-Message-State: APjAAAXckonvkKmEJbb0bXpA2rlZTMAi23GqU/fffg992xReOT9S3rvT YXGjuvEXKMEqL5MHIA2iSRWh1ImGEFbWfCwXXVjclQ== X-Google-Smtp-Source: APXvYqzJ78Hp+J0EQOUH7hmwCA6ls2xSoGkR+p3ZYGSQevYWjXtzfJblxbeqTO0P8uf32WdUMdXjL5e/b1QEEU8BVsQ= X-Received: by 2002:a2e:96c6:: with SMTP id d6mr11906253ljj.4.1581614134958; Thu, 13 Feb 2020 09:15:34 -0800 (PST) MIME-Version: 1.0 References: <20200212133715.GU3420@suse.de> <20200212194903.GS3466@techsingularity.net> <20200213131658.9600-1-hdanton@sina.com> <20200213134655.GX3466@techsingularity.net> <20200213150026.GB6541@lorien.usersys.redhat.com> <20200213151430.GY3466@techsingularity.net> <20200213163437.GZ3466@techsingularity.net> <20200213170220.GA3466@techsingularity.net> In-Reply-To: <20200213170220.GA3466@techsingularity.net> From: Vincent Guittot Date: Thu, 13 Feb 2020 18:15:23 +0100 Message-ID: Subject: Re: [RFC 2/4] sched/numa: replace runnable_load_avg by load_avg To: Mel Gorman Cc: Phil Auld , Hillf Danton , Ingo Molnar , Peter Zijlstra , Juri Lelli , Dietmar Eggemann , Steven Rostedt , Ben Segall , linux-kernel , Parth Shah , Valentin Schneider Content-Type: text/plain; charset="UTF-8" Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Thu, 13 Feb 2020 at 18:02, Mel Gorman wrote: > > On Thu, Feb 13, 2020 at 05:38:31PM +0100, Vincent Guittot wrote: > > > > Your test doesn't explicitly ensure that the 1 condition is met > > > > > > > > That being said, I'm not sure it's really a wrong thing ? I mean > > > > load_balance will probably try to pull back some tasks on src but as > > > > long as it is not a task with dst node as preferred node, it should > > > > not be that harmfull > > > > > > My thinking was that if source has as many or more running tasks than > > > the destination *after* the move that it's not harmful and does not add > > > work for the load balancer. > > > > load_balancer will see an imbalance but fbq_classify_group/queue > > should be there to prevent from pulling back tasks that are on the > > preferred node but only other tasks > > > > Yes, exactly. Between fbq_classify and migrate_degrades_locality, I'm > expecting that the load balancer will only override NUMA balancing when > there is no better option. When the imbalance check, I want to avoid > the situation where NUMA balancing moves a task for locality, LB pulls > it back for balance, NUMA retries the move etc because it's stupid. The > locality matters but being continually dequeue/enqueue is unhelpful. > > While there might be grounds for relaxing the degree an imbalance is > allowed across SD domains, I am avoiding looking in that direction again > until the load balancer and NUMA balancer stop overriding each other for > silly reasons (or the NUMA balancer fighting itself which can happen). make sense > > -- > Mel Gorman > SUSE Labs