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=-5.5 required=3.0 tests=BAYES_00, HEADER_FROM_DIFFERENT_DOMAINS,MAILING_LIST_MULTI,NICE_REPLY_A,SPF_HELO_NONE, SPF_PASS,URIBL_BLOCKED,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 51EB0C433DB for ; Fri, 22 Jan 2021 10:13:01 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id F0971238EE for ; Fri, 22 Jan 2021 10:13:00 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1727830AbhAVKMl (ORCPT ); Fri, 22 Jan 2021 05:12:41 -0500 Received: from foss.arm.com ([217.140.110.172]:39312 "EHLO foss.arm.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1727226AbhAVKG3 (ORCPT ); Fri, 22 Jan 2021 05:06:29 -0500 Received: from usa-sjc-imap-foss1.foss.arm.com (unknown [10.121.207.14]) by usa-sjc-mx-foss1.foss.arm.com (Postfix) with ESMTP id 46FE111D4; Fri, 22 Jan 2021 02:05:30 -0800 (PST) Received: from [192.168.178.6] (unknown [172.31.20.19]) by usa-sjc-imap-foss1.foss.arm.com (Postfix) with ESMTPSA id C4A2B3F719; Fri, 22 Jan 2021 02:05:28 -0800 (PST) Subject: Re: 5.11-rc4+git: Shortest NUMA path spans too many nodes To: "Song Bao Hua (Barry Song)" , Valentin Schneider , Meelis Roos , LKML Cc: Peter Zijlstra , Vincent Guittot , Mel Gorman References: <3ec17983-7959-eccd-af25-400056a5877d@linux.ee> <8797fd78-4367-bc5c-3a35-43c544c745e4@linux.ee> <353d255769b6463c862993e2329a9a8d@hisilicon.com> From: Dietmar Eggemann Message-ID: <99ecee86-8d96-c1e2-5b38-8f3dfcc38bd1@arm.com> Date: Fri, 22 Jan 2021 11:05:08 +0100 User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:68.0) Gecko/20100101 Thunderbird/68.10.0 MIME-Version: 1.0 In-Reply-To: <353d255769b6463c862993e2329a9a8d@hisilicon.com> Content-Type: text/plain; charset=utf-8 Content-Language: en-US Content-Transfer-Encoding: 7bit Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On 21/01/2021 22:17, Song Bao Hua (Barry Song) wrote: > > >> -----Original Message----- >> From: Dietmar Eggemann [mailto:dietmar.eggemann@arm.com] >> Sent: Friday, January 22, 2021 7:54 AM >> To: Valentin Schneider ; Meelis Roos >> ; LKML >> Cc: Peter Zijlstra ; Vincent Guittot >> ; Song Bao Hua (Barry Song) >> ; Mel Gorman >> Subject: Re: 5.11-rc4+git: Shortest NUMA path spans too many nodes >> >> On 21/01/2021 19:21, Valentin Schneider wrote: >>> On 21/01/21 19:39, Meelis Roos wrote: [...] >> # cat /sys/devices/system/node/node*/distance >> 10 12 12 14 14 14 14 16 >> 12 10 14 12 14 14 12 14 >> 12 14 10 14 12 12 14 14 >> 14 12 14 10 12 12 14 14 >> 14 14 12 12 10 14 12 14 >> 14 14 12 12 14 10 14 12 >> 14 12 14 14 12 14 10 12 >> 16 14 14 14 14 12 12 10 >> >> The '16' seems to be the culprit. How does such a topo look like? Maybe like this: _________ | | .-6 0 4-. | \ / \ / | | 1 2 | | \ \ | --7 3----5 | | |____|_| |_______| > > Once we get a topology like this: > > > +------+ +------+ +-------+ +------+ > | node | |node | | node | |node | > | +---------+ +--------+ +-------+ | > +------+ +------+ +-------+ +------+ > > We can reproduce this issue. > For example, every cpu with the below numa_distance can have > "groups don't span domain->span": > node 0 1 2 3 > 0: 10 12 20 22 > 1: 12 10 22 24 > 2: 20 22 10 12 > 3: 22 24 12 10 2 20 2 So this should look like: 1 --- 0 ---- 2 --- 3