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=-2.2 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 3E91EC35677 for ; Mon, 24 Feb 2020 03:09:13 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id 076CA20675 for ; Mon, 24 Feb 2020 03:09:13 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1727213AbgBXDJL (ORCPT ); Sun, 23 Feb 2020 22:09:11 -0500 Received: from out30-56.freemail.mail.aliyun.com ([115.124.30.56]:47240 "EHLO out30-56.freemail.mail.aliyun.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1727156AbgBXDJL (ORCPT ); Sun, 23 Feb 2020 22:09:11 -0500 X-Alimail-AntiSpam: AC=PASS;BC=-1|-1;BR=01201311R231e4;CH=green;DM=||false|;DS=||;FP=0|-1|-1|-1|0|-1|-1|-1;HT=e01f04455;MF=yun.wang@linux.alibaba.com;NM=1;PH=DS;RN=18;SR=0;TI=SMTPD_---0Tqhg-oW_1582513746; Received: from testdeMacBook-Pro.local(mailfrom:yun.wang@linux.alibaba.com fp:SMTPD_---0Tqhg-oW_1582513746) by smtp.aliyun-inc.com(127.0.0.1); Mon, 24 Feb 2020 11:09:08 +0800 Subject: Re: [PATCH RESEND v8 1/2] sched/numa: introduce per-cgroup NUMA locality info To: Peter Zijlstra Cc: Mel Gorman , Ingo Molnar , Juri Lelli , Vincent Guittot , Dietmar Eggemann , Steven Rostedt , Ben Segall , Luis Chamberlain , Kees Cook , Iurii Zaikin , Michal Koutn? , linux-fsdevel@vger.kernel.org, linux-kernel@vger.kernel.org, linux-doc@vger.kernel.org, "Paul E. McKenney" , Randy Dunlap , Jonathan Corbet References: <20200214151048.GL14914@hirez.programming.kicks-ass.net> <20200217115810.GA3420@suse.de> <881deb50-163e-442a-41ec-b375cc445e4d@linux.alibaba.com> <20200221152824.GH18400@hirez.programming.kicks-ass.net> From: =?UTF-8?B?546L6LSH?= Message-ID: <3bd3f4d0-2504-a48c-adea-a28227a81d7a@linux.alibaba.com> Date: Mon, 24 Feb 2020 11:09:06 +0800 User-Agent: Mozilla/5.0 (Macintosh; Intel Mac OS X 10.13; rv:68.0) Gecko/20100101 Thunderbird/68.4.1 MIME-Version: 1.0 In-Reply-To: <20200221152824.GH18400@hirez.programming.kicks-ass.net> Content-Type: text/plain; charset=utf-8 Content-Language: en-US Content-Transfer-Encoding: 8bit Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On 2020/2/21 δΈ‹εˆ11:28, Peter Zijlstra wrote: > On Mon, Feb 17, 2020 at 09:23:52PM +0800, ηŽ‹θ΄‡ wrote: >> FYI, by monitoring locality, we found that the kvm vcpu thread is not >> covered by NUMA Balancing, whatever how many maximum period passed, the >> counters are not increasing, or very slowly, although inside guest we are >> copying memory. >> >> Later we found such task rarely exit to user space to trigger task >> work callbacks, and NUMA Balancing scan depends on that, which help us >> realize the importance to enable NUMA Balancing inside guest, with the >> correct NUMA topo, a big performance risk I'll say :-P > > That's a bug in KVM, see: > > https://lkml.kernel.org/r/20190801143657.785902257@linutronix.de > https://lkml.kernel.org/r/20190801143657.887648487@linutronix.de > > ISTR there being newer versions of that patch-set, but I can't seem to > find them in a hurry. Aha, that's exactly the problem we saw, will check~ Regards, Michael Wang >