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 0EFCAC0015E for ; Mon, 3 Jul 2023 15:30:08 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S230423AbjGCPaG (ORCPT ); Mon, 3 Jul 2023 11:30:06 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:59334 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S229793AbjGCP37 (ORCPT ); Mon, 3 Jul 2023 11:29:59 -0400 Received: from foss.arm.com (foss.arm.com [217.140.110.172]) by lindbergh.monkeyblade.net (Postfix) with ESMTP id 4022AE49; Mon, 3 Jul 2023 08:29:58 -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 B76132F4; Mon, 3 Jul 2023 08:30:40 -0700 (PDT) Received: from [10.57.27.93] (unknown [10.57.27.93]) by usa-sjc-imap-foss1.foss.arm.com (Postfix) with ESMTPSA id 7AEAA3F663; Mon, 3 Jul 2023 08:29:55 -0700 (PDT) Message-ID: <18b1a981-79a0-13d7-bfba-2f1c0e554da9@arm.com> Date: Mon, 3 Jul 2023 16:30:13 +0100 MIME-Version: 1.0 User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:102.0) Gecko/20100101 Thunderbird/102.11.0 Subject: Re: [PATCH v2 12/17] PM: EM: Add argument to get_cost() for runtime modification Content-Language: en-US To: Dietmar Eggemann Cc: rui.zhang@intel.com, amit.kucheria@verdurent.com, amit.kachhap@gmail.com, daniel.lezcano@linaro.org, viresh.kumar@linaro.org, len.brown@intel.com, pavel@ucw.cz, Pierre.Gondois@arm.com, ionela.voinescu@arm.com, rostedt@goodmis.org, mhiramat@kernel.org, linux-kernel@vger.kernel.org, linux-pm@vger.kernel.org, rafael@kernel.org References: <20230512095743.3393563-1-lukasz.luba@arm.com> <20230512095743.3393563-13-lukasz.luba@arm.com> <93afb0fd-6226-4b0d-380a-182ecf028b34@arm.com> From: Lukasz Luba In-Reply-To: <93afb0fd-6226-4b0d-380a-182ecf028b34@arm.com> Content-Type: text/plain; charset=UTF-8; format=flowed Content-Transfer-Encoding: 7bit Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On 5/30/23 10:53, Dietmar Eggemann wrote: > On 12/05/2023 11:57, Lukasz Luba wrote: >> The Energy Model (EM) supports runtime modifications. Let also the >> artificial EM use this new feature and allow to update the 'cost' values >> at runtime. When the artificial EM is used there is a need to provide >> two callbacks: get_cost() and update_power(), not only the last one. >> >> Update also CPPC driver code, since the new argument is needed there >> to compile properly and register EM. > > Is there a real use case behind this? It can't be mobile which IMHO > drivers the rest of the 'Runtime modifiable EM' feature. Correct, CPPC+EM is not for mobile phones, but notebooks. For now the notebooks are not tested with that feature and were not in requirement scope. > > Do we know of any machine using the artificial EM. And do they care > about EM matching workload or static power? > > [...] For now we don't know about such notebook which uses CPPC + EM and if it's a candidate for this feature. I thought, since it's just one patch w/ small change, it would be consistent to not 'forget' about that notebooks angle. I know that there are some folks who 'run'/'are willing to run' Arm laptop with CPPC w/ artificial EM. They might pick that feature as well.