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=-2.5 required=3.0 tests=HEADER_FROM_DIFFERENT_DOMAINS, MAILING_LIST_MULTI,SPF_HELO_NONE,SPF_PASS,UNPARSEABLE_RELAY,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 3704CC5ACAE for ; Wed, 11 Sep 2019 14:02:23 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id 1215C206CD for ; Wed, 11 Sep 2019 14:02:22 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1728095AbfIKOCW (ORCPT ); Wed, 11 Sep 2019 10:02:22 -0400 Received: from out30-57.freemail.mail.aliyun.com ([115.124.30.57]:46094 "EHLO out30-57.freemail.mail.aliyun.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1726626AbfIKOCV (ORCPT ); Wed, 11 Sep 2019 10:02:21 -0400 X-Alimail-AntiSpam: AC=PASS;BC=-1|-1;BR=01201311R251e4;CH=green;DM=||false|;FP=0|-1|-1|-1|0|-1|-1|-1;HT=e01f04391;MF=aaron.lu@linux.alibaba.com;NM=1;PH=DS;RN=22;SR=0;TI=SMTPD_---0Tc4oLSS_1568210525; Received: from aaronlu(mailfrom:aaron.lu@linux.alibaba.com fp:SMTPD_---0Tc4oLSS_1568210525) by smtp.aliyun-inc.com(127.0.0.1); Wed, 11 Sep 2019 22:02:12 +0800 Date: Wed, 11 Sep 2019 22:02:05 +0800 From: Aaron Lu To: Tim Chen , Julien Desfossez Cc: Dario Faggioli , "Li, Aubrey" , Aubrey Li , Subhra Mazumdar , Vineeth Remanan Pillai , Nishanth Aravamudan , Peter Zijlstra , Ingo Molnar , Thomas Gleixner , Paul Turner , Linus Torvalds , Linux List Kernel Mailing , =?iso-8859-1?Q?Fr=E9d=E9ric?= Weisbecker , Kees Cook , Greg Kerr , Phil Auld , Valentin Schneider , Mel Gorman , Pawan Gupta , Paolo Bonzini Subject: Re: [RFC PATCH v3 00/16] Core scheduling v3 Message-ID: <20190911140204.GA52872@aaronlu> References: <20190619183302.GA6775@sinkpad> <20190718100714.GA469@aaronlu> <20190725143003.GA992@aaronlu> <20190726152101.GA27884@sinkpad> <7dc86e3c-aa3f-905f-3745-01181a3b0dac@linux.intel.com> <20190802153715.GA18075@sinkpad> <69cd9bca-da28-1d35-3913-1efefe0c1c22@linux.intel.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: User-Agent: Mutt/1.5.21 (2010-09-15) Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Hi Tim & Julien, On Fri, Sep 06, 2019 at 11:30:20AM -0700, Tim Chen wrote: > On 8/7/19 10:10 AM, Tim Chen wrote: > > > 3) Load balancing between CPU cores > > ----------------------------------- > > Say if one CPU core's sibling threads get forced idled > > a lot as it has mostly incompatible tasks between the siblings, > > moving the incompatible load to other cores and pulling > > compatible load to the core could help CPU utilization. > > > > So just considering the load of a task is not enough during > > load balancing, task compatibility also needs to be considered. > > Peter has put in mechanisms to balance compatible tasks between > > CPU thread siblings, but not across cores. > > > > Status: > > I have not seen patches on this issue. This issue could lead to > > large variance in workload performance based on your luck > > in placing the workload among the cores. > > > > I've made an attempt in the following two patches to address > the load balancing of mismatched load between the siblings. > > It is applied on top of Aaron's patches: > - sched: Fix incorrect rq tagged as forced idle > - wrapper for cfs_rq->min_vruntime > https://lore.kernel.org/lkml/20190725143127.GB992@aaronlu/ > - core vruntime comparison > https://lore.kernel.org/lkml/20190725143248.GC992@aaronlu/ So both of you are working on top of my 2 patches that deal with the fairness issue, but I had the feeling Tim's alternative patches[1] are simpler than mine and achieves the same result(after the force idle tag fix), so unless there is something I missed, I think we should go with the simpler one? [1]: https://lore.kernel.org/lkml/b7a83fcb-5c34-9794-5688-55c52697fd84@linux.intel.com/