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 Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by smtp.lore.kernel.org (Postfix) with ESMTP id 0E6C0C433F5 for ; Fri, 13 May 2022 08:36:46 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1378379AbiEMIgo (ORCPT ); Fri, 13 May 2022 04:36:44 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:48124 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1378276AbiEMIgl (ORCPT ); Fri, 13 May 2022 04:36:41 -0400 Received: from foss.arm.com (foss.arm.com [217.140.110.172]) by lindbergh.monkeyblade.net (Postfix) with ESMTP id 208A426272A for ; Fri, 13 May 2022 01:36:40 -0700 (PDT) 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 ED0F7113E; Fri, 13 May 2022 01:36:39 -0700 (PDT) Received: from [192.168.178.6] (unknown [172.31.20.19]) by usa-sjc-imap-foss1.foss.arm.com (Postfix) with ESMTPSA id DB1DB3F73D; Fri, 13 May 2022 01:36:38 -0700 (PDT) Message-ID: <4b124aa9-ed26-a40b-8e74-81043d051247@arm.com> Date: Fri, 13 May 2022 10:36:26 +0200 MIME-Version: 1.0 User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:91.0) Gecko/20100101 Thunderbird/91.8.1 Subject: Re: [PATCH V2] arch_topology: support parsing cluster_id from DT Content-Language: en-US To: Sudeep Holla , Qing Wang Cc: Greg Kroah-Hartman , "Rafael J. Wysocki" , linux-kernel@vger.kernel.org References: <1652262776-3056-1-git-send-email-wangqing@vivo.com> From: Dietmar Eggemann In-Reply-To: Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 7bit Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On 12/05/2022 16:17, Sudeep Holla wrote: > On Wed, May 11, 2022 at 02:52:56AM -0700, Qing Wang wrote: >> From: Wang Qing >> >> Use nested cluster structures in DT to support describing multi-level >> cluster topologies and increase the parsing of nested cluster. >> >> Notice: the clusters describing in DT currently are not physical >> boundaries, since changing "cluster" to "socket" is too involved and error >> prone, this patch will not have any effect on one-level cluster topo, but >> can support the mutil-level cluster topo to support CLUSTER_SCHED. > > Sorry the socket/package_id is broken. If we are playing with cluster_id > which is now wrongly presented as package_id, you are forced to fix that > too. We don't want to break that in a different way or leave that as is > since the cluster_id and package ids now show up as same now. Earlier the > cluster_id was -1. We can leave package_id=0 (and maybe add socket parsing later) and use llc_id instead. Like some Arm server do via ACPI. This will leave cluster_id for Armv9 L2 sharing. cluster_id is also used in servers for 2. level "clustering", e.g. Kunpeng920 L3-tags or Ampere Altra's SCU boundaries. This way we can achieve both. (1) not use package_id for cluster and (2) have cluster_id available for 2. level cluster. I just send out a lightly tested RFC: https://lkml.kernel.org/r/20220513083400.343706-1-dietmar.eggemann@arm.com > > I had a look when I started reviewing your patch. Assuming we don't need > nested cluster support yet, I have some patches(not built or tested > unfortunately yet). Let me know your thoughts. If you think you still > need support for some kind of nested cluster, build that on top of this. > Also I haven't bothered about sched domains as this purely relates to > topology and how this is mapped to sched domain is orthogonal. > > If anything is broken, that needs to be fixed separately there. I see the > idea here is correct and would like to push the patches once I build/test > and get some review/more testing.