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=-5.3 required=3.0 tests=BAYES_00, HEADER_FROM_DIFFERENT_DOMAINS,MAILING_LIST_MULTI,NICE_REPLY_A,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 820E0C433B4 for ; Thu, 1 Apr 2021 08:45:19 +0000 (UTC) Received: from lists.gnu.org (lists.gnu.org [209.51.188.17]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by mail.kernel.org (Postfix) with ESMTPS id C1492610A0 for ; Thu, 1 Apr 2021 08:45:18 +0000 (UTC) DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org C1492610A0 Authentication-Results: mail.kernel.org; dmarc=fail (p=none dis=none) header.from=huawei.com Authentication-Results: mail.kernel.org; spf=pass smtp.mailfrom=qemu-devel-bounces+qemu-devel=archiver.kernel.org@nongnu.org Received: from localhost ([::1]:42630 helo=lists1p.gnu.org) by lists.gnu.org with esmtp (Exim 4.90_1) (envelope-from ) id 1lRsx3-00008C-Sy for qemu-devel@archiver.kernel.org; Thu, 01 Apr 2021 04:45:17 -0400 Received: from eggs.gnu.org ([2001:470:142:3::10]:41948) by lists.gnu.org with esmtps (TLS1.2:ECDHE_RSA_AES_256_GCM_SHA384:256) (Exim 4.90_1) (envelope-from ) id 1lRsvB-0007ew-LH; Thu, 01 Apr 2021 04:43:21 -0400 Received: from szxga02-in.huawei.com ([45.249.212.188]:2133) by eggs.gnu.org with esmtps (TLS1.2:ECDHE_RSA_AES_256_GCM_SHA384:256) (Exim 4.90_1) (envelope-from ) id 1lRsv3-0008VL-Nq; Thu, 01 Apr 2021 04:43:20 -0400 Received: from DGGEML404-HUB.china.huawei.com (unknown [172.30.72.56]) by szxga02-in.huawei.com (SkyGuard) with ESMTP id 4F9xV507Xwz5ktx; Thu, 1 Apr 2021 16:41:01 +0800 (CST) Received: from dggpemm500023.china.huawei.com (7.185.36.83) by DGGEML404-HUB.china.huawei.com (10.3.17.39) with Microsoft SMTP Server (TLS) id 14.3.498.0; Thu, 1 Apr 2021 16:43:06 +0800 Received: from [10.174.187.128] (10.174.187.128) by dggpemm500023.china.huawei.com (7.185.36.83) with Microsoft SMTP Server (version=TLS1_2, cipher=TLS_ECDHE_RSA_WITH_AES_128_CBC_SHA256) id 15.1.2106.2; Thu, 1 Apr 2021 16:43:05 +0800 Subject: Re: [RFC PATCH 0/6] Introduce cluster cpu topology support To: Paolo Bonzini , , References: <20210331095343.12172-1-wangyanan55@huawei.com> <20162bd1-b31e-e180-8792-81934e0d005b@redhat.com> From: "wangyanan (Y)" Message-ID: <1cddde6a-3338-70f0-1d4c-d6fd5d634bb3@huawei.com> Date: Thu, 1 Apr 2021 16:43:05 +0800 User-Agent: Mozilla/5.0 (Windows NT 10.0; Win64; x64; rv:78.0) Gecko/20100101 Thunderbird/78.4.0 MIME-Version: 1.0 In-Reply-To: <20162bd1-b31e-e180-8792-81934e0d005b@redhat.com> Content-Type: text/plain; charset="utf-8"; format=flowed Content-Transfer-Encoding: 7bit Content-Language: en-US X-Originating-IP: [10.174.187.128] X-ClientProxiedBy: dggeme717-chm.china.huawei.com (10.1.199.113) To dggpemm500023.china.huawei.com (7.185.36.83) X-CFilter-Loop: Reflected Received-SPF: pass client-ip=45.249.212.188; envelope-from=wangyanan55@huawei.com; helo=szxga02-in.huawei.com X-Spam_score_int: -41 X-Spam_score: -4.2 X-Spam_bar: ---- X-Spam_report: (-4.2 / 5.0 requ) BAYES_00=-1.9, NICE_REPLY_A=-0.001, RCVD_IN_DNSWL_MED=-2.3, SPF_HELO_NONE=0.001, SPF_PASS=-0.001 autolearn=ham autolearn_force=no X-Spam_action: no action X-BeenThere: qemu-devel@nongnu.org X-Mailman-Version: 2.1.23 Precedence: list List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Cc: Barry Song , Peter Maydell , Andrew Jones , Eduardo Habkost , "Michael S . Tsirkin" , Richard Henderson , Shannon Zhao , wanghaibin.wang@huawei.com, yuzenghui@huawei.com, Igor Mammedov , zhukeqian1@huawei.com, Jiajie Li Errors-To: qemu-devel-bounces+qemu-devel=archiver.kernel.org@nongnu.org Sender: "Qemu-devel" Hi Paolo, On 2021/3/31 18:00, Paolo Bonzini wrote: > On 31/03/21 11:53, Yanan Wang wrote: >> A cluster means a group of cores that share some resources (e.g. cache) >> among them under the LLC. For example, ARM64 server chip Kunpeng 920 has >> 6 or 8 clusters in each NUMA, and each cluster has 4 cores. All clusters >> share L3 cache data while cores within each cluster share the L2 cache. > > Is this different from what we already have with "-smp dies"? As far as I know, yes. I think they are two architecture concepts of different levels. A cpu socket/package can consist of multiple dies, and each die can consist of multiple clusters, which means dies are parent for clusters. And this kind of cpu hierarchy structure is normal in ARM64 platform. Still take above ARM64 server chip Kunpeng 920 as an example, there totally are 2 sockets, 2 dies in each socket, 6 or 8 clusters in each die, and 4 cores in each cluster. Since it also supports NUMA architecture, then each NUMA actually represents one die. Although there is already "-smp dies=*" command line parameter for PC Machines, a cluster level can be added for x86 architecture if meaningful and there will be more work to do in qemu to make use of it. And I am sure that ARM needs this level. If there is something wrong above, please correct me, thanks! Thanks, Yanan > > Paolo > > .