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[23.128.96.18]) by mx.google.com with ESMTP id b3si3204398edr.570.2021.05.27.15.06.38; Thu, 27 May 2021 15:07:01 -0700 (PDT) Received-SPF: pass (google.com: domain of linux-kernel-owner@vger.kernel.org designates 23.128.96.18 as permitted sender) client-ip=23.128.96.18; Authentication-Results: mx.google.com; spf=pass (google.com: domain of linux-kernel-owner@vger.kernel.org designates 23.128.96.18 as permitted sender) smtp.mailfrom=linux-kernel-owner@vger.kernel.org; dmarc=fail (p=NONE sp=NONE dis=NONE) header.from=arm.com Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S236844AbhE0PLC (ORCPT + 99 others); Thu, 27 May 2021 11:11:02 -0400 Received: from foss.arm.com ([217.140.110.172]:58974 "EHLO foss.arm.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S236879AbhE0PKV (ORCPT ); Thu, 27 May 2021 11:10:21 -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 0CCFD11D4; Thu, 27 May 2021 08:08:46 -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 5379F3F73B; Thu, 27 May 2021 08:08:44 -0700 (PDT) Subject: Re: [PATCH v5 2/3] sched/topology: Rework CPU capacity asymmetry detection To: Beata Michalska Cc: Valentin Schneider , linux-kernel@vger.kernel.org, peterz@infradead.org, mingo@redhat.com, juri.lelli@redhat.com, vincent.guittot@linaro.org, corbet@lwn.net, rdunlap@infradead.org, linux-doc@vger.kernel.org References: <20210524101617.8965-1-beata.michalska@arm.com> <20210524101617.8965-3-beata.michalska@arm.com> <87fsyc6mfz.mognet@arm.com> <20210524225508.GA14880@e120325.cambridge.arm.com> <87a6oj6sxo.mognet@arm.com> <20210525102945.GA24210@e120325.cambridge.arm.com> <98ad8837-b9b8-ff50-5a91-8d5951ee757c@arm.com> <20210526121546.GA13262@e120325.cambridge.arm.com> <20210526125133.GB13262@e120325.cambridge.arm.com> <20210526214004.GA1712@e120325.cambridge.arm.com> From: Dietmar Eggemann Message-ID: <14593ba7-eed9-f035-724c-5cadbb859adc@arm.com> Date: Thu, 27 May 2021 17:08:42 +0200 User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:78.0) Gecko/20100101 Thunderbird/78.8.1 MIME-Version: 1.0 In-Reply-To: <20210526214004.GA1712@e120325.cambridge.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 26/05/2021 23:40, Beata Michalska wrote: > On Wed, May 26, 2021 at 08:17:41PM +0200, Dietmar Eggemann wrote: >> On 26/05/2021 14:51, Beata Michalska wrote: >>> On Wed, May 26, 2021 at 01:15:46PM +0100, Beata Michalska wrote: >>>> On Wed, May 26, 2021 at 11:52:25AM +0200, Dietmar Eggemann wrote: >>>>> On 25/05/2021 12:29, Beata Michalska wrote: >>>>>> On Tue, May 25, 2021 at 10:53:07AM +0100, Valentin Schneider wrote: >>>>>>> On 24/05/21 23:55, Beata Michalska wrote: >>>>>>>> On Mon, May 24, 2021 at 07:01:04PM +0100, Valentin Schneider wrote: >>>>>>>>> On 24/05/21 11:16, Beata Michalska wrote: [...] >> cpu-map { >> cluster0 { >> core0 { >> thread0 { >> cpu = <&A53_0>; >> }; >> thread1 { >> cpu = <&A53_1>; >> }; >> }; >> core1 { >> thread0 { >> cpu = <&A53_2>; >> }; >> thread1 { >> cpu = <&A53_3>; >> }; >> }; >> core2 { >> thread0 { >> cpu = <&A53_4>; >> }; >> thread1 { >> cpu = <&A53_5>; >> }; >> }; >> }; >> >> cluster1 { >> core0 { >> thread0 { >> cpu = <&A53_6>; >> }; >> thread1 { >> cpu = <&A53_7>; >> }; >> }; >> }; >> }; >> >> A53_0: cpu@0 { >> capacity-dmips-mhz = <446>; >> A53_1: cpu@1 { >> capacity-dmips-mhz = <1024>; >> A53_2: cpu@2 { >> capacity-dmips-mhz = <871>; >> A53_3: cpu@3 { >> capacity-dmips-mhz = <1024>; >> A53_4: cpu@4 { >> capacity-dmips-mhz = <446>; >> A53_5: cpu@5 { >> capacity-dmips-mhz = <871>; >> A53_6: cpu@6 { >> capacity-dmips-mhz = <1024>; >> A53_7: cpu@7 { >> capacity-dmips-mhz = <1024>; >> >> Here I guess SD_ASYM_CPUCAPACITY will be attached to SMT[0-5]. So this >> 'capacity-dmips-mhz' config error won't be detected. >> >> In case all CPUs (i.e. hw threads would have the correct >> capacity-dmips-mhz = <1024> or not being set (default 1024)) >> asym_cap_list would corrcetly only have 1 entry. > We could possibly add a warning (like in EAS) if the asymmetry is detected > for SMT which would give some indication that there is smth ... wrong ? Maybe, in case you find an easy way to detect this. But the issue already exists today. Not with the topology mentioned above but in case we slightly change it to: cpus = { ([446 1024] [871 1024] [446 1024] ) ([1024 1024]) } ^^^^ so that we have a 1024 CPU in the lowest sd for each CPU, we would get SD_ASYM_CPUCAPACITY on SMT.