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 94EA5C433F5 for ; Mon, 7 Feb 2022 12:04:58 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1391774AbiBGMDB (ORCPT ); Mon, 7 Feb 2022 07:03:01 -0500 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:55262 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1385880AbiBGLpB (ORCPT ); Mon, 7 Feb 2022 06:45:01 -0500 Received: from foss.arm.com (foss.arm.com [217.140.110.172]) by lindbergh.monkeyblade.net (Postfix) with ESMTP id CB145C0401ED; Mon, 7 Feb 2022 03:44:48 -0800 (PST) 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 258F911B3; Mon, 7 Feb 2022 03:44:48 -0800 (PST) Received: from [10.57.15.201] (unknown [10.57.15.201]) by usa-sjc-imap-foss1.foss.arm.com (Postfix) with ESMTPSA id 31D9B3F70D; Mon, 7 Feb 2022 03:44:45 -0800 (PST) Subject: Re: [PATCH 0/2] Ignore Energy Model with abstract scale in IPA and DTPM To: Daniel Lezcano Cc: amit.kachhap@gmail.com, viresh.kumar@linaro.org, rafael@kernel.org, amitk@kernel.org, rui.zhang@intel.com, dietmar.eggemann@arm.com, Pierre.Gondois@arm.com, linux-kernel@vger.kernel.org, linux-pm@vger.kernel.org References: <20220207073036.14901-1-lukasz.luba@arm.com> <0d2217e0-44f7-8587-3e1f-a73d301ab166@linaro.org> From: Lukasz Luba Message-ID: <616307f7-b419-8e36-6879-6cf6f4e02d5a@arm.com> Date: Mon, 7 Feb 2022 11:44:44 +0000 User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:78.0) Gecko/20100101 Thunderbird/78.14.0 MIME-Version: 1.0 In-Reply-To: <0d2217e0-44f7-8587-3e1f-a73d301ab166@linaro.org> Content-Type: text/plain; charset=utf-8; format=flowed Content-Language: en-US Content-Transfer-Encoding: 7bit Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On 2/7/22 10:41 AM, Daniel Lezcano wrote: > On 07/02/2022 08:30, Lukasz Luba wrote: >> Hi all, >> >> The Energy Model supports abstract scale power values. This might cause >> issues for some mechanisms like thermal governor IPA or DTPM, which >> expect that all devices provide sane power values. This patch set >> prevents >> from registering such devices for IPA and DTPM. > > > Does it mean for example big and little have both 0-100 ? > > Unfortunately, these can be any numbers. I hope at least the CPUs Big and Little power have sense: Little power is not higher than Big power. The purpose of EM is to enable EAS, so this power relation between Big and Little should have sense. Someone who is not willing to or cannot expose real power values, still wants the EAS to operate (my assumption and hope). The SCMI FW can provide abstract power values. It's in the SCMI spec. Thus, creating these abstract scale power values for big.LITTLE the right way should result in properly working EAS. I can also have hope for GPU vs. Big power, but it is a weaker hope. The second is more tricky to distinguish even if you have a domain knowledge, but not the real measurements with you. The GPU power values is also a 'sensitive' knowledge to share. Open source guys can do that (after measurements), but some vendor's engineers probably can't.