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 4240BC07E95 for ; Wed, 7 Jul 2021 10:23:59 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 62CAC61C9D for ; Wed, 7 Jul 2021 10:23:58 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S231384AbhGGK0h (ORCPT ); Wed, 7 Jul 2021 06:26:37 -0400 Received: from foss.arm.com ([217.140.110.172]:33810 "EHLO foss.arm.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S231153AbhGGK0g (ORCPT ); Wed, 7 Jul 2021 06:26:36 -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 3D1BB1063; Wed, 7 Jul 2021 03:23:56 -0700 (PDT) Received: from [10.57.1.129] (unknown [10.57.1.129]) by usa-sjc-imap-foss1.foss.arm.com (Postfix) with ESMTPSA id 1D39F3F694; Wed, 7 Jul 2021 03:23:52 -0700 (PDT) Subject: Re: [PATCH 2/3] PM: EM: Make em_cpu_energy() able to return bigger values To: Peter Zijlstra Cc: linux-kernel@vger.kernel.org, Chris.Redpath@arm.com, dietmar.eggemann@arm.com, morten.rasmussen@arm.com, qperret@google.com, linux-pm@vger.kernel.org, rjw@rjwysocki.net, viresh.kumar@linaro.org, vincent.guittot@linaro.org, mingo@redhat.com, juri.lelli@redhat.com, rostedt@goodmis.org, segall@google.com, mgorman@suse.de, bristot@redhat.com, CCj.Yeh@mediatek.com References: <20210625152603.25960-1-lukasz.luba@arm.com> <20210625152603.25960-3-lukasz.luba@arm.com> From: Lukasz Luba Message-ID: Date: Wed, 7 Jul 2021 11:23:51 +0100 User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:60.0) Gecko/20100101 Thunderbird/60.9.0 MIME-Version: 1.0 In-Reply-To: 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 7/7/21 11:01 AM, Peter Zijlstra wrote: > On Wed, Jul 07, 2021 at 09:09:08AM +0100, Lukasz Luba wrote: >> For now we would live with this simple code which improves >> all recent 64bit platforms and is easy to take it into Android >> common kernel. The next step would be more scattered across >> other subsystems, so harder to backport to Android 5.4 and others. > > Ah, you *do* only care about 64bit :-) So one option is to only increase > precision for 64BIT builds, just like we do for scale_load() and > friends. > Your suggestion is potentially a good compromise :-) We could leave the 32bit alone and they would have old code and precision. Thank you for the comments. Let me discuss this internally with my team.