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=-2.1 required=3.0 tests=DKIM_INVALID,DKIM_SIGNED, 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 70DD7C35646 for ; Fri, 21 Feb 2020 15:28:52 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id 3F7B424653 for ; Fri, 21 Feb 2020 15:28:52 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=fail reason="signature verification failed" (2048-bit key) header.d=infradead.org header.i=@infradead.org header.b="FO11uySW" Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1729175AbgBUP2t (ORCPT ); Fri, 21 Feb 2020 10:28:49 -0500 Received: from bombadil.infradead.org ([198.137.202.133]:37552 "EHLO bombadil.infradead.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1729072AbgBUP2p (ORCPT ); Fri, 21 Feb 2020 10:28:45 -0500 DKIM-Signature: v=1; a=rsa-sha256; q=dns/txt; c=relaxed/relaxed; d=infradead.org; s=bombadil.20170209; h=In-Reply-To:Content-Transfer-Encoding :Content-Type:MIME-Version:References:Message-ID:Subject:Cc:To:From:Date: Sender:Reply-To:Content-ID:Content-Description; bh=teQadSX0wyV4ftQ41M/03hMOBJ7nffcslPnRS4n1cL0=; b=FO11uySWYfI+CHf4sRD/ycCuie nHo0JseQxPLSNhugXNfrjWpNpFYClG0EJ6ZhsJjnA4J8gErKszWCl2gM2wO95J1dA7ORGjeTOGc1r ACXPYJgq/Z/oTLUEJHHzz7Xdsva/ZoWzEWoZzpXzjqmFOpHtcqXLVo1H7eqSwhMds4sMo58AJLwd3 DQxRWRpw/60TICg7PHg/Yvr/nKsTJozL7slseewvBlRg2iJclSKEdCwigvnRCsG6s3/W0LVfgx8Gx I7ZnmxVYGvd9qPsMMO2IjpDbUYh/g62/J/7dywfdJbrXUmeZ4kb5O7zWAqdEeFzLy6xXDrQmkLmQd n1fjTRkQ==; Received: from j217100.upc-j.chello.nl ([24.132.217.100] helo=noisy.programming.kicks-ass.net) by bombadil.infradead.org with esmtpsa (Exim 4.92.3 #3 (Red Hat Linux)) id 1j5AE7-0001jI-81; Fri, 21 Feb 2020 15:28:27 +0000 Received: from hirez.programming.kicks-ass.net (hirez.programming.kicks-ass.net [192.168.1.225]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (Client did not present a certificate) by noisy.programming.kicks-ass.net (Postfix) with ESMTPS id D4B5D306151; Fri, 21 Feb 2020 16:26:30 +0100 (CET) Received: by hirez.programming.kicks-ass.net (Postfix, from userid 1000) id 29990209DB0F7; Fri, 21 Feb 2020 16:28:24 +0100 (CET) Date: Fri, 21 Feb 2020 16:28:24 +0100 From: Peter Zijlstra To: =?utf-8?B?546L6LSH?= 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 Subject: Re: [PATCH RESEND v8 1/2] sched/numa: introduce per-cgroup NUMA locality info Message-ID: <20200221152824.GH18400@hirez.programming.kicks-ass.net> References: <20200214151048.GL14914@hirez.programming.kicks-ass.net> <20200217115810.GA3420@suse.de> <881deb50-163e-442a-41ec-b375cc445e4d@linux.alibaba.com> MIME-Version: 1.0 Content-Type: text/plain; charset=utf-8 Content-Disposition: inline Content-Transfer-Encoding: 8bit In-Reply-To: <881deb50-163e-442a-41ec-b375cc445e4d@linux.alibaba.com> User-Agent: Mutt/1.10.1 (2018-07-13) Sender: linux-fsdevel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-fsdevel@vger.kernel.org On Mon, Feb 17, 2020 at 09:23:52PM +0800, 王贇 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.