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=-2.6 required=3.0 tests=DKIMWL_WL_HIGH,DKIM_SIGNED, DKIM_VALID,DKIM_VALID_AU,MAILING_LIST_MULTI,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 F02FBC5DF62 for ; Wed, 6 Nov 2019 09:22:12 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id BC864217F4 for ; Wed, 6 Nov 2019 09:22:12 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=default; t=1573032132; bh=M9G0HwhgUSpx80ddg4nMBBHD3OELZdSYi1Usddbm0R8=; h=Date:From:To:Cc:Subject:References:In-Reply-To:List-ID:From; b=Q6PpFFLYpKZ14QslHyZ9xd9L7EmaC6zsKpWzho4vgno8A/qyzJdtyLDd76klrOczd 4i4Kctvr0NHtWYY28KiuEW8PsPwPy+AFInz/dOl6/EXeyIy+7DODR8CsXyrTy+qxd1 OiZhOCgcsEFQNBrULam8MUB5GH952TvOr966KOH8= Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1731550AbfKFJWL (ORCPT ); Wed, 6 Nov 2019 04:22:11 -0500 Received: from mx2.suse.de ([195.135.220.15]:36770 "EHLO mx1.suse.de" rhost-flags-OK-OK-OK-FAIL) by vger.kernel.org with ESMTP id S1727041AbfKFJWL (ORCPT ); Wed, 6 Nov 2019 04:22:11 -0500 X-Virus-Scanned: by amavisd-new at test-mx.suse.de Received: from relay2.suse.de (unknown [195.135.220.254]) by mx1.suse.de (Postfix) with ESMTP id 82F36AC8C; Wed, 6 Nov 2019 09:22:09 +0000 (UTC) Date: Wed, 6 Nov 2019 10:22:08 +0100 From: Michal Hocko To: Shaokun Zhang Cc: Andrew Morton , linux-kernel@vger.kernel.org, yuqi jin , Mike Rapoport , Paul Burton , Michael Ellerman , Anshuman Khandual Subject: Re: [PATCH v2] lib: optimize cpumask_local_spread() Message-ID: <20191106092208.GE8314@dhcp22.suse.cz> References: <1572863268-28585-1-git-send-email-zhangshaokun@hisilicon.com> <20191105070141.GF22672@dhcp22.suse.cz> <20191105173359.39052327cf221d9c4b26b783@linux-foundation.org> <20191106071742.GB8314@dhcp22.suse.cz> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: User-Agent: Mutt/1.10.1 (2018-07-13) Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Wed 06-11-19 16:02:29, Shaokun Zhang wrote: > Hi Michal, > > On 2019/11/6 15:17, Michal Hocko wrote: > > On Tue 05-11-19 17:33:59, Andrew Morton wrote: > >> On Tue, 5 Nov 2019 08:01:41 +0100 Michal Hocko wrote: > >> > >>> On Mon 04-11-19 18:27:48, Shaokun Zhang wrote: > >>>> From: yuqi jin > >>>> > >>>> In the multi-processor and NUMA system, I/O device may have many numa > >>>> nodes belonging to multiple cpus. When we get a local numa, it is > >>>> better to find the node closest to the local numa node, instead > >>>> of choosing any online cpu immediately. > >>>> > >>>> For the current code, it only considers the local NUMA node and it > >>>> doesn't compute the distances between different NUMA nodes for the > >>>> non-local NUMA nodes. Let's optimize it and find the nearest node > >>>> through NUMA distance. The performance will be better if it return > >>>> the nearest node than the random node. > >>> > >>> Numbers please > >> > >> The changelog had > >> > >> : When Parameter Server workload is tested using NIC device on Huawei > >> : Kunpeng 920 SoC: > >> : Without the patch, the performance is 22W QPS; > >> : Added this patch, the performance become better and it is 26W QPS. > > > > Maybe it is just me but this doesn't really tell me a lot. What is > > Parameter Server workload? What do I do to replicate those numbers? Is > > I will give it better description on it in next version. Since it returns > the nearest node from the non-local node than the random one, no harmless > to others, Right? Well, I am not really familiar with consumers of this API to understand the full consequences and that is why I keep asking. From a very highlevel POV prefering CPUs on the same NUMA domain sounds like a reasonable thing to do. -- Michal Hocko SUSE Labs