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,DKIM_SIGNED, DKIM_VALID,DKIM_VALID_AU,HEADER_FROM_DIFFERENT_DOMAINS,MAILING_LIST_MULTI, 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 D9A88C2D0A3 for ; Fri, 6 Nov 2020 09:24:46 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 7A294208B3 for ; Fri, 6 Nov 2020 09:24:46 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=pass (2048-bit key) header.d=linaro.org header.i=@linaro.org header.b="XSb/jGpB" Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1725893AbgKFJYp (ORCPT ); Fri, 6 Nov 2020 04:24:45 -0500 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:52332 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1726345AbgKFJYp (ORCPT ); Fri, 6 Nov 2020 04:24:45 -0500 Received: from mail-pf1-x443.google.com (mail-pf1-x443.google.com [IPv6:2607:f8b0:4864:20::443]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 13CB9C0613D2 for ; Fri, 6 Nov 2020 01:24:45 -0800 (PST) Received: by mail-pf1-x443.google.com with SMTP id y7so755694pfq.11 for ; Fri, 06 Nov 2020 01:24:45 -0800 (PST) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=linaro.org; s=google; h=date:from:to:cc:subject:message-id:references:mime-version :content-disposition:in-reply-to:user-agent; bh=hzarJxo5HuHRgVKDtpQt++8Xgz0VtleRQQlUu1Y/EL4=; b=XSb/jGpBPw+cVJcyj0jTuj3LMjz1JkiKTojGtKjtw7LBVCVJ7DjJcMgMw759u8pitr aY6Aa2QEnu44wDFhMrjgU5wvsWC7caBgH4z7Q6BJPn7tNsZJuDDe5bJvuM92UQFcRTpy 7N68/Ed7KR2G8ZMzRd2VDRytZ3WszN8BpJaULEAzofL44cj3M6QSf3nfLYEowIATGgl6 onN0odWpJSSzY853vJdXgR1edW2A4OseA4cBiflBm997cccgWatVtBE8DXW5CiIk8GPB GLruobY+Q2YjuU03L45lgWHCGAjl+za4S4SCiZpORwhuVHz0NJjdmr537zw3Cx561/aC j5rw== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20161025; h=x-gm-message-state:date:from:to:cc:subject:message-id:references :mime-version:content-disposition:in-reply-to:user-agent; bh=hzarJxo5HuHRgVKDtpQt++8Xgz0VtleRQQlUu1Y/EL4=; b=Y2sxI8bhAjrJeKOUpECAt7qu5YD662Bh2/i2WagkBrJv2xArbceWD9vbGS5zyp0+cF iPWQcma1WViqmh0G1iHJIV6DH9QWrUVpsat+iwK8xegecUy2GMXKZSqZj0wFz8X0Wrq6 LLVxqsGQ2fBJTnQgJv6M0J39gA7MwFit8dPP+lezPLMatXvzhgYkn7oG100KzO9bWM1t YFeE2E2rVhE0HL+CwgIm1vm8x5Gc/GnQoGT+e6GBAx4Rcc9XKIAbu10D4iOCBQ7drvNT O+GP0CVtjUxF7yQ7ybQjIBWr+YLDsf8x/orrHPClTRSy0T55njxD+jnYzl58l7ey33DB K4EQ== X-Gm-Message-State: AOAM531PV9DIyPLJQOlWI7AH+Q2dW6Wz877FvgK2olb7/gAQmrD8yDzG IBgHNCnSywtZoCeLQdEhWExz0A== X-Google-Smtp-Source: ABdhPJwK+R4KBhdhJw4U0BZWFmXUL2OPqquUHVrPTHZktlF9Q8+WJHzzEM94OCY1zmZGgP6/TYhrkQ== X-Received: by 2002:a63:5466:: with SMTP id e38mr1022850pgm.23.1604654684629; Fri, 06 Nov 2020 01:24:44 -0800 (PST) Received: from localhost ([122.172.12.172]) by smtp.gmail.com with ESMTPSA id 136sm1362968pfb.152.2020.11.06.01.24.43 (version=TLS1_2 cipher=ECDHE-ECDSA-AES128-GCM-SHA256 bits=128/128); Fri, 06 Nov 2020 01:24:44 -0800 (PST) Date: Fri, 6 Nov 2020 14:54:42 +0530 From: Viresh Kumar To: Nicola Mazzucato Cc: linux-kernel@vger.kernel.org, linux-arm-kernel@lists.infradead.org, linux-pm@vger.kernel.org, devicetree@vger.kernel.org, sudeep.holla@arm.com, rjw@rjwysocki.net, vireshk@kernel.org, robh+dt@kernel.org, sboyd@kernel.org, nm@ti.com, daniel.lezcano@linaro.org, morten.rasmussen@arm.com, chris.redpath@arm.com Subject: Re: [PATCH v3 3/3] [RFC] CPUFreq: Add support for cpu-perf-dependencies Message-ID: <20201106092442.v5fao2dyl3lemwyh@vireshk-i7> References: <20201102120115.29993-1-nicola.mazzucato@arm.com> <20201102120115.29993-4-nicola.mazzucato@arm.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20201102120115.29993-4-nicola.mazzucato@arm.com> User-Agent: NeoMutt/20180716-391-311a52 Precedence: bulk List-ID: X-Mailing-List: devicetree@vger.kernel.org On 02-11-20, 12:01, Nicola Mazzucato wrote: > Hi All, > > This is a continuation of the previous v2, where we focused mostly on the > dt binding. > > I am seeking some feedback/comments on the following two approaches. > > Intro: > We have seen that in a system where performance control and hardware > description do not match (i.e. per-cpu), we still need the information of > how the v/f lines are shared among the cpus. We call this information > "performance dependencies". > We got this info through the opp-shared (the previous 2 patches aim for > that). > > Problem: > How do we share such info (retrieved from a cpufreq driver) to other > consumers that rely on it? I have two proposals. FWIW, we already have a case in kernel where something similar is done. commit f4fd3797848a ("acpi-cpufreq: Add new sysfs attribute freqdomain_cpus") and the information is shared via: /sys/devices/system/cpu/cpu#/cpufreq/freqdomain_cpus -- viresh