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=-8.6 required=3.0 tests=DKIMWL_WL_HIGH,DKIM_SIGNED, DKIM_VALID,DKIM_VALID_AU,HEADER_FROM_DIFFERENT_DOMAINS,INCLUDES_PATCH, MAILING_LIST_MULTI,SIGNED_OFF_BY,SPF_PASS,USER_AGENT_MUTT autolearn=ham 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 C2CD8C282D7 for ; Wed, 30 Jan 2019 19:07:09 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id 868B32087F for ; Wed, 30 Jan 2019 19:07:09 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=pass (1024-bit key) header.d=chromium.org header.i=@chromium.org header.b="W0eNB8pc" Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S2387468AbfA3THH (ORCPT ); Wed, 30 Jan 2019 14:07:07 -0500 Received: from mail-pg1-f195.google.com ([209.85.215.195]:38199 "EHLO mail-pg1-f195.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1727628AbfA3THG (ORCPT ); Wed, 30 Jan 2019 14:07:06 -0500 Received: by mail-pg1-f195.google.com with SMTP id g189so230035pgc.5 for ; Wed, 30 Jan 2019 11:07:05 -0800 (PST) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=chromium.org; s=google; h=date:from:to:cc:subject:message-id:references:mime-version :content-disposition:in-reply-to:user-agent; bh=9duydc19GYN8AxYc5ag4AZR+rk+raFykoe6IFlo6h3k=; b=W0eNB8pcKJgPJTItR89wwfj6aqagd11pPHm9zBuwQ0sFOODe45mDZkSO21jyuhA3jF RuucgKnorNCqMRuWrFeoRD2uiWyVT8HTPPix8Q5dXiwWGJDbyjdP9bl1/IGx95hfQZWg oFHmTxQtxzgrOMp4/7Aocib9HjLLvehH7DREc= 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=9duydc19GYN8AxYc5ag4AZR+rk+raFykoe6IFlo6h3k=; b=dSF8/a6Q2qhnXUF4RDbyvOCxAokGbq32bHCKvWOQj9tE45d/DADCwYwPFG71YPv5+8 2cNJFUtVtiQF4TgSivU5tnmhQxDCoky/hCmRn+K8XSCwJBPChEojSulme57eyAllZiwH zMDgV5WnYDK7qTJcEI9qIP8mT80ikyurZTRbEJM0ZrtKsaJxIXJqnpxuNyksWoqDx4er PmJ+/LEcXq929Ed2AkvYgF5YvMJaXJkY9rPmOlwrd1OPtBdP9qfwindFvrRrqmMA4fxU Kg5WO+Me0NBieG5RidFYi3nwN5KSXGfvyecAG1bdtFfDSD1RIO4g2uuGSk8W+6sE7vh7 c7mw== X-Gm-Message-State: AJcUuke5MfjyAZ4KtKSGGAIUdxPdWJjX/DYz26p8wI7q4HQ6b/YS6B8k U7z3ltudECVfl3HBMH15PTXdTA== X-Google-Smtp-Source: ALg8bN6MJCpntz8Z6TXacjN/a0N92GEZgcdiwaA7z44fMrJfbD2UyjtSUsSpkG5Gz/nFRG8upiOaww== X-Received: by 2002:a63:587:: with SMTP id 129mr28321887pgf.273.1548875225077; Wed, 30 Jan 2019 11:07:05 -0800 (PST) Received: from localhost ([2620:15c:202:1:75a:3f6e:21d:9374]) by smtp.gmail.com with ESMTPSA id p77sm4603429pfi.85.2019.01.30.11.07.04 (version=TLS1_2 cipher=ECDHE-RSA-CHACHA20-POLY1305 bits=256/256); Wed, 30 Jan 2019 11:07:04 -0800 (PST) Date: Wed, 30 Jan 2019 11:07:03 -0800 From: Matthias Kaehlcke To: Quentin Perret Cc: viresh.kumar@linaro.org, sudeep.holla@arm.com, rjw@rjwysocki.net, nm@ti.com, sboyd@kernel.org, linux-pm@vger.kernel.org, linux-kernel@vger.kernel.org, linux-arm-kernel@lists.infradead.org, dietmar.eggemann@arm.com Subject: Re: [PATCH v2 1/5] PM / OPP: Introduce a power estimation helper Message-ID: <20190130190703.GM81583@google.com> References: <20190130170506.20450-1-quentin.perret@arm.com> <20190130170506.20450-2-quentin.perret@arm.com> MIME-Version: 1.0 Content-Type: text/plain; charset=utf-8 Content-Disposition: inline In-Reply-To: <20190130170506.20450-2-quentin.perret@arm.com> User-Agent: Mutt/1.10.1 (2018-07-13) Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Hi Quentin, On Wed, Jan 30, 2019 at 05:05:02PM +0000, Quentin Perret wrote: > The Energy Model (EM) framework provides an API to let drivers register > the active power of CPUs. The drivers are expected to provide a callback > method which estimates the power consumed by a CPU at each available > performance levels. How exactly this should be implemented, however, > depends on the platform. > > On some systems, PM_OPP knows the voltage and frequency at which CPUs > can run. When coupled with the CPU 'capacitance' (as provided by the > 'dynamic-power-coefficient' devicetree binding), it is possible to > estimate the dynamic power consumption of a CPU as P = C * V^2 * f, with > C its capacitance and V and f respectively the voltage and frequency of > the OPP. The Intelligent Power Allocator (IPA) thermal governor already > implements that estimation method, in the thermal framework. > > However, this power estimation method can be applied to any platform > where all the parameters are known (C, V and f), and not only those > suffering thermal issues. As such, the code implementing this feature > can be re-used to also populate the EM framework now used by EAS. > > As a first step, introduce in PM_OPP a helper function which CPUFreq > drivers can use to register into the EM framework. This duplicates the > power estimation done in IPA until it can be migrated to using the EM > framework. This will be done later, once the EM framework has support > for at least all platforms currently supported by IPA. > > Signed-off-by: Quentin Perret > > --- > > Matthias: Given this patch changed a bit I dropped your Reviewed-by and > Tested-by, but let me know if you think they still hold. > --- > drivers/opp/of.c | 88 ++++++++++++++++++++++++++++++++++++++++++ > include/linux/pm_opp.h | 6 +++ > 2 files changed, 94 insertions(+) > > diff --git a/drivers/opp/of.c b/drivers/opp/of.c > index 06f0f632ec47..4c8bf172e9ed 100644 > --- a/drivers/opp/of.c > +++ b/drivers/opp/of.c > @@ -20,6 +20,7 @@ > #include > #include > #include > +#include nit: AFAIK typically alphabetical order is used for includes, though this file doesn't exactly adhere to it. > #include "opp.h" > > @@ -1047,3 +1048,90 @@ struct device_node *dev_pm_opp_get_of_node(struct dev_pm_opp *opp) > return of_node_get(opp->np); > } > EXPORT_SYMBOL_GPL(dev_pm_opp_get_of_node); > + > +/* > + * Callback function provided to the Energy Model framework upon registration. > + * This computes the power estimated by @CPU at the first OPP above @kHz (ceil), that's not entirely correct, it could be the OPP at @kHz. > + * and updates @kHz and @mW accordingly. The power is estimated as > + * P = C * V^2 * f with C being the CPU's capacitance and V and f respectively > + * the voltage and frequency of the OPP. > + * > + * Returns -ENODEV if the CPU device cannot be found, -EINVAL if the power > + * calculation failed because of missing parameters, 0 otherwise. > + */ > +static int __maybe_unused _get_cpu_power(unsigned long *mW, unsigned long *kHz, > + int cpu) why __maybe_unused? > +{ > + struct device *cpu_dev; > + struct dev_pm_opp *opp; > + struct device_node *np; > + unsigned long mV, Hz; > + u32 cap; > + u64 tmp; > + int ret; > + > + cpu_dev = get_cpu_device(cpu); > + if (!cpu_dev) > + return -ENODEV; > + > + np = of_node_get(cpu_dev->of_node); > + if (!np) > + return -EINVAL; > + > + ret = of_property_read_u32(np, "dynamic-power-coefficient", &cap); > + of_node_put(np); > + if (ret) > + return -EINVAL; > + > + Hz = *kHz * 1000; > + opp = dev_pm_opp_find_freq_ceil(cpu_dev, &Hz); > + if (IS_ERR(opp)) > + return -EINVAL; > + > + mV = dev_pm_opp_get_voltage(opp) / 1000; > + dev_pm_opp_put(opp); > + if (!mV) > + return -EINVAL; > + > + tmp = (u64)cap * mV * mV * (Hz / 1000000); > + do_div(tmp, 1000000000); > + > + *mW = (unsigned long)tmp; > + *kHz = Hz / 1000; > + > + return 0; > +} > + > +/** > + * dev_pm_opp_of_register_em() - Attempt to register an Energy Model > + * @cpus : CPUs for which an Energy Model has to be registered > + * @nr_opp : Number of OPPs to register in the Energy Model > + * > + * This checks whether the "dynamic-power-coefficient" devicetree binding has s/binding/property/ ? > + * been specified, and tries to register an Energy Model with it if it has. > + */ > +void dev_pm_opp_of_register_em(struct cpumask *cpus, int nr_opp) Is the nr_opp parameter really needed? The function looks up the CPU device and hence could determine the OPP count itself with dev_pm_opp_get_opp_count(). I see most cpufreq drivers call dev_pm_opp_get_opp_count() anyway, so passing the count as parameter can be considered a small optimization, not sure how relevant it is though, since dev_pm_opp_of_register_em() isn't called frequently. > +{ > + struct em_data_callback em_cb = EM_DATA_CB(_get_cpu_power); > + int ret, cpu = cpumask_first(cpus); > + struct device *cpu_dev; > + struct device_node *np; > + u32 cap; > + > + cpu_dev = get_cpu_device(cpu); > + if (!cpu_dev) > + return; > + > + np = of_node_get(cpu_dev->of_node); > + if (!np) > + return; > + > + /* Don't register an EM without the right DT binding */ > + ret = of_property_read_u32(np, "dynamic-power-coefficient", &cap); > + of_node_put(np); > + if (ret || !cap) > + return; > + > + em_register_perf_domain(cpus, nr_opp, &em_cb); > +} > +EXPORT_SYMBOL_GPL(dev_pm_opp_of_register_em); > diff --git a/include/linux/pm_opp.h b/include/linux/pm_opp.h > index b895f4e79868..58ae08b024bd 100644 > --- a/include/linux/pm_opp.h > +++ b/include/linux/pm_opp.h > @@ -327,6 +327,7 @@ int dev_pm_opp_of_get_sharing_cpus(struct device *cpu_dev, struct cpumask *cpuma > struct device_node *dev_pm_opp_of_get_opp_desc_node(struct device *dev); > struct device_node *dev_pm_opp_get_of_node(struct dev_pm_opp *opp); > int of_get_required_opp_performance_state(struct device_node *np, int index); > +void dev_pm_opp_of_register_em(struct cpumask *cpus, int nr_opp); > #else > static inline int dev_pm_opp_of_add_table(struct device *dev) > { > @@ -365,6 +366,11 @@ static inline struct device_node *dev_pm_opp_get_of_node(struct dev_pm_opp *opp) > { > return NULL; > } > + > +static inline void dev_pm_opp_of_register_em(struct cpumask *cpus, int nr_opp) > +{ > +} > + > static inline int of_get_required_opp_performance_state(struct device_node *np, int index) > { > return -ENOTSUPP; Tested-by: Matthias Kaehlcke