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 AAA8BC433B4 for ; Fri, 16 Apr 2021 10:39:44 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 86BE3610CD for ; Fri, 16 Apr 2021 10:39:44 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S241709AbhDPKkG (ORCPT ); Fri, 16 Apr 2021 06:40:06 -0400 Received: from foss.arm.com ([217.140.110.172]:38402 "EHLO foss.arm.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S235267AbhDPKj6 (ORCPT ); Fri, 16 Apr 2021 06:39:58 -0400 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 1A03D106F; Fri, 16 Apr 2021 03:39:34 -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 C72573FA35; Fri, 16 Apr 2021 03:39:31 -0700 (PDT) Subject: Re: [PATCH v2 0/1] arm: topology: parse the topology from the dt To: Valentin Schneider , Ruifeng Zhang Cc: linux@armlinux.org.uk, sudeep.holla@arm.com, Greg KH , "Rafael J. Wysocki" , a.p.zijlstra@chello.nl, mingo@kernel.org, ruifeng.zhang1@unisoc.com, nianfu.bai@unisoc.com, linux-arm-kernel@lists.infradead.org, Linux Kernel Mailing List References: <20210414122326.5255-1-ruifeng.zhang0110@gmail.com> <8735vrmnc7.mognet@arm.com> <87wnt2lglo.mognet@arm.com> From: Dietmar Eggemann Message-ID: <44ab835f-3456-6bd9-97e9-5936cf5372da@arm.com> Date: Fri, 16 Apr 2021 12:39:30 +0200 User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:78.0) Gecko/20100101 Thunderbird/78.7.1 MIME-Version: 1.0 In-Reply-To: <87wnt2lglo.mognet@arm.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 16/04/2021 11:32, Valentin Schneider wrote: > On 16/04/21 15:47, Ruifeng Zhang wrote: >> For more requirements, if all cores in one physical cluster, the >> {aff2} of all cores are the same value. >> i.e. the sc9863a, >> core0: 0000000081000000 >> core1: 0000000081000100 >> core2: 0000000081000200 >> core3: 0000000081000300 >> core4: 0000000081000400 >> core5: 0000000081000500 >> core6: 0000000081000600 >> core7: 0000000081000700 >> >> According to MPIDR all cores will parse to the one cluster, but it's >> the big.LITTLE system, it's need two logic cluster for schedule or >> cpufreq. >> So I think it's better to add the logic of parse topology from DT. > > Ah, so it's a slightly different issue, but still one that requires a > different means of specifying topology. I'm confused. Do you have the MT bit set to 1 then? So the issue that the mpidr handling in arm32's store_cpu_topology() is not correct does not exist? With DynamIQ you have only *one* cluster, you should also be able to run your big.LITTLE system with only an MC sched domain. # cat /proc/schedstat cpu0 .... domain0 ff ... <- MC ... You can introduce a cpu-map to create what we called Phantom Domains in Android products. # cat /proc/schedstat cpu0 .... domain0 0f ... <- MC domain1 ff ... < DIE Is this what you need for your arm32 kernel system? Adding the possibility to parse cpu-map to create Phantom Domains?