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=-8.4 required=3.0 tests=DKIM_SIGNED,DKIM_VALID, DKIM_VALID_AU,HEADER_FROM_DIFFERENT_DOMAINS,INCLUDES_PATCH,MAILING_LIST_MULTI, SIGNED_OFF_BY,SPF_HELO_NONE,SPF_PASS,USER_AGENT_SANE_1 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 A6AB2C432C0 for ; Tue, 26 Nov 2019 08:03:21 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id 68DFC20722 for ; Tue, 26 Nov 2019 08:03:21 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=pass (2048-bit key) header.d=linaro.org header.i=@linaro.org header.b="TSNPciRP" Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1727341AbfKZIDU (ORCPT ); Tue, 26 Nov 2019 03:03:20 -0500 Received: from mail-pl1-f193.google.com ([209.85.214.193]:38329 "EHLO mail-pl1-f193.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1725817AbfKZIDU (ORCPT ); Tue, 26 Nov 2019 03:03:20 -0500 Received: by mail-pl1-f193.google.com with SMTP id o8so3417782pls.5 for ; Tue, 26 Nov 2019 00:03:19 -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=+Q0EDEuSC1u9SRsCtaYMm2HqYxfYcQCWFv26nwXdP88=; b=TSNPciRPB+Wn14eBFRY9yhgWXttjm8ce5Jh2h/hUX30QdqmCAVDr0uZagN3zl6AqFG Axdlr+zAukr8VHLEVmK2VRtWBTuRndYriMhf8KoC+Foy/b9Iy48QHhkW7ZD3Ws8YUwHp oBBEsNviGPm9kmUgTSuX295kNHgIlo3umvGj6f/9MHetnh1ZuZDT31D8JSD/sVhSiRE0 TuAb3swJ3bVi4TbVCvWTv3tdtvfXt3ugCajw8IARxZuVlY+OfwLRHzrjWG9GykLBXC72 CDdirefiXfPcD6BqlT2F8yhtW2oTO9rYBD0Gl/gI1irlh42JWoaVZs1DAni3Oj+x1cxY WneA== 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=+Q0EDEuSC1u9SRsCtaYMm2HqYxfYcQCWFv26nwXdP88=; b=NPDoTG35dd1d0rjMV/cAW7G2I2q8ITMljeJI35d55BPHCJiyuZ8VijcabhntmgYzZZ 1gxje1IcwJ1YtePimLs1FxaXWNlluxmzN1X72y4jsW6FjRBBUeoiC39orM8mZkra4GqL z+cR+tg+AwmD8v9OhzOO4BHbaEfzvSxtB0x+lhLnUb4ghwJN7c5Z40em2qt6HXCUodSO AOVTHoJvLFKz3tQDXglYOkoaxS5qMroyS0SEra7lgVvvKYssITNfzzga74qQRjRU8kif HilyKVjI8wENabfNUCYB1SLSy9XY4SQ7Q32tvcjArKL/jZklujbC4Yc+KqMOaN7vFr1w w9Cw== X-Gm-Message-State: APjAAAUpYkhCkMJcdkInm0aVxvye3QS4JDc+6PcWxoreFunEsutI1hFm trlPY1kuVUaq+kGfL3KlrSySBg== X-Google-Smtp-Source: APXvYqwGuYe6wNEFduKxK/jznJLleNsDVzbsINjaQFryXM06oPnryx0LV3AOZ3dRyy33jwQEkxJRXw== X-Received: by 2002:a17:902:a410:: with SMTP id p16mr32541741plq.184.1574755399008; Tue, 26 Nov 2019 00:03:19 -0800 (PST) Received: from localhost ([122.171.112.123]) by smtp.gmail.com with ESMTPSA id k5sm1927711pju.14.2019.11.26.00.03.17 (version=TLS1_2 cipher=ECDHE-RSA-AES128-GCM-SHA256 bits=128/128); Tue, 26 Nov 2019 00:03:17 -0800 (PST) Date: Tue, 26 Nov 2019 13:33:15 +0530 From: Viresh Kumar To: Daniel Lezcano Cc: rjw@rjwysocki.net, edubezval@gmail.com, rui.zhang@intel.com, linux-pm@vger.kernel.org, amit.kucheria@linaro.org, linux-kernel@vger.kernel.org Subject: Re: [PATCH 3/3] thermal/drivers/cpu_cooling: Introduce the cpu idle cooling driver Message-ID: <20191126080315.zc5rllbsc5utuhzq@vireshk-i7> References: <20191113084042.5707-1-daniel.lezcano@linaro.org> <20191113084042.5707-3-daniel.lezcano@linaro.org> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20191113084042.5707-3-daniel.lezcano@linaro.org> User-Agent: NeoMutt/20180716-391-311a52 Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On 13-11-19, 09:40, Daniel Lezcano wrote: > The cpu idle cooling device offers a new method to cool down a CPU by > injecting idle cycles at runtime. > > It has some similarities with the intel power clamp driver but it is > actually designed to be more generic and relying on the idle injection > powercap framework. > > The idle injection cycle is fixed while the running cycle is variable. That > allows to have control on the device reactivity for the user experience. > > An idle state powering down the CPU or the cluster will allow to drop > the static leakage, thus restoring the heat capacity of the SoC. It > can be set with a trip point between the hot and the critical points, > giving the opportunity to prevent a hard reset of the system when the > cpufreq cooling fails to cool down the CPU. > > With more sophisticated boards having a per core sensor, the idle > cooling device allows to cool down a single core without throttling > the compute capacity of several cpus belonging to the same clock line, > so it could be used in collaboration with the cpufreq cooling device. > > Signed-off-by: Daniel Lezcano > --- > drivers/thermal/Kconfig | 7 + > drivers/thermal/Makefile | 1 + > drivers/thermal/cpuidle_cooling.c | 233 ++++++++++++++++++++++++++++++ > include/linux/cpu_cooling.h | 22 +++ > 4 files changed, 263 insertions(+) > create mode 100644 drivers/thermal/cpuidle_cooling.c > > diff --git a/drivers/thermal/Kconfig b/drivers/thermal/Kconfig > index 2b82c4861091..00d69906c508 100644 > --- a/drivers/thermal/Kconfig > +++ b/drivers/thermal/Kconfig > @@ -168,6 +168,13 @@ config CPU_FREQ_THERMAL > This will be useful for platforms using the generic thermal interface > and not the ACPI interface. > > +config CPU_IDLE_THERMAL > + bool "CPU idle cooling device" > + depends on IDLE_INJECT > + help > + This implements the CPU cooling mechanism through > + idle injection. This will throttle the CPU by injecting > + idle cycle. > endif > > config CLOCK_THERMAL > diff --git a/drivers/thermal/Makefile b/drivers/thermal/Makefile > index d3b01cc96981..9c8aa2d4bd28 100644 > --- a/drivers/thermal/Makefile > +++ b/drivers/thermal/Makefile > @@ -20,6 +20,7 @@ thermal_sys-$(CONFIG_THERMAL_GOV_POWER_ALLOCATOR) += power_allocator.o > > # cpufreq cooling > thermal_sys-$(CONFIG_CPU_FREQ_THERMAL) += cpu_cooling.o We should really rename this as cpufreq_cooling now :) > +thermal_sys-$(CONFIG_CPU_IDLE_THERMAL) += cpuidle_cooling.o > > # clock cooling > thermal_sys-$(CONFIG_CLOCK_THERMAL) += clock_cooling.o > diff --git a/drivers/thermal/cpuidle_cooling.c b/drivers/thermal/cpuidle_cooling.c > new file mode 100644 > index 000000000000..6e911fa87c47 > --- /dev/null > +++ b/drivers/thermal/cpuidle_cooling.c > @@ -0,0 +1,233 @@ > +// SPDX-License-Identifier: GPL-2.0 > +/* > + * Copyright (C) 2019 Linaro Limited. > + * > + * Author: Daniel Lezcano > + * > + */ > +#include > +#include > +#include > +#include > +#include > +#include > +#include > + > +/** > + * struct cpuidle_cooling_device - data for the idle cooling device > + * @ii_dev: an atomic to keep track of the last task exiting the idle cycle > + * @idle_duration_us: an integer defining the duration of the idle injection > + * @state: an normalized integer giving the state of the cooling device > + */ > +struct cpuidle_cooling_device { > + struct idle_inject_device *ii_dev; > + unsigned int idle_duration_us; This field is set with TICK_USEC and nothing else. Why not just use TICK_USEC instead at all the places and remove this field? > + unsigned long state; > +}; > + > +static DEFINE_IDA(cpuidle_ida); > + > +/** > + * cpuidle_cooling_runtime - Running time computation > + * @idle_duration_us: the idle cooling device > + * @state: a percentile based number > + * > + * The running duration is computed from the idle injection duration > + * which is fixed. If we reach 100% of idle injection ratio, that > + * means the running duration is zero. If we have a 50% ratio > + * injection, that means we have equal duration for idle and for > + * running duration. > + * > + * The formula is deduced as the following: > + * > + * running = idle x ((100 / ratio) - 1) > + * > + * For precision purpose for integer math, we use the following: > + * > + * running = (idle x 100) / ratio - idle > + * > + * For example, if we have an injected duration of 50%, then we end up > + * with 10ms of idle injection and 10ms of running duration. > + * > + * Returns an unsigned int for an usec based runtime duration. > + */ > +static unsigned int cpuidle_cooling_runtime(unsigned int idle_duration_us, > + unsigned long state) > +{ > + if (!state) > + return 0; > + > + return ((idle_duration_us * 100) / state) - idle_duration_us; > +} > + > +/** > + * cpuidle_cooling_get_max_state - Get the maximum state > + * @cdev : the thermal cooling device > + * @state : a pointer to the state variable to be filled > + * > + * The function always gives 100 as the injection ratio is percentile > + * based for consistency accros different platforms. > + * > + * The function can not fail, it always returns zero. > + */ > +static int cpuidle_cooling_get_max_state(struct thermal_cooling_device *cdev, > + unsigned long *state) > +{ > + /* > + * Depending on the configuration or the hardware, the running > + * cycle and the idle cycle could be different. We want unify > + * that to an 0..100 interval, so the set state interface will > + * be the same whatever the platform is. > + * > + * The state 100% will make the cluster 100% ... idle. A 0% > + * injection ratio means no idle injection at all and 50% > + * means for 10ms of idle injection, we have 10ms of running > + * time. > + */ > + *state = 100; > + > + return 0; > +} > + > +/** > + * cpuidle_cooling_get_cur_state - Get the current cooling state > + * @cdev: the thermal cooling device > + * @state: a pointer to the state > + * > + * The function just copy the state value from the private thermal > + * cooling device structure, the mapping is 1 <-> 1. > + * > + * The function can not fail, it always returns zero. > + */ > +static int cpuidle_cooling_get_cur_state(struct thermal_cooling_device *cdev, > + unsigned long *state) > +{ > + struct cpuidle_cooling_device *idle_cdev = cdev->devdata; > + > + *state = idle_cdev->state; > + > + return 0; > +} > + > +/** > + * cpuidle_cooling_set_cur_state - Set the current cooling state > + * @cdev: the thermal cooling device > + * @state: the target state > + * > + * The function checks first if we are initiating the mitigation which > + * in turn wakes up all the idle injection tasks belonging to the idle > + * cooling device. In any case, it updates the internal state for the > + * cooling device. > + * > + * The function can not fail, it always returns zero. > + */ > +static int cpuidle_cooling_set_cur_state(struct thermal_cooling_device *cdev, > + unsigned long state) > +{ > + struct cpuidle_cooling_device *idle_cdev = cdev->devdata; > + struct idle_inject_device *ii_dev = idle_cdev->ii_dev; > + unsigned long current_state = idle_cdev->state; > + unsigned int runtime_us; > + > + idle_cdev->state = state; > + > + runtime_us = cpuidle_cooling_runtime(idle_cdev->idle_duration_us, > + state); > + > + idle_inject_set_duration(ii_dev, runtime_us, > + idle_cdev->idle_duration_us); > + > + if (current_state == 0 && state > 0) { > + idle_inject_start(ii_dev); > + } else if (current_state > 0 && !state) { > + idle_inject_stop(ii_dev); > + } > + > + return 0; > +} > + > +/** > + * cpuidle_cooling_ops - thermal cooling device ops > + */ > +static struct thermal_cooling_device_ops cpuidle_cooling_ops = { > + .get_max_state = cpuidle_cooling_get_max_state, > + .get_cur_state = cpuidle_cooling_get_cur_state, > + .set_cur_state = cpuidle_cooling_set_cur_state, > +}; > + > +/** > + * cpuidle_of_cooling_register - Idle cooling device initialization function > + * @drv: a cpuidle driver structure pointer > + * > + * This function is in charge of creating a cooling device per cpuidle > + * driver and register it to thermal framework. > + * > + * Returns a valid pointer to a thermal cooling device, a PTR_ERR > + * corresponding to the error detected in the underlying subsystems. > + */ > +struct thermal_cooling_device * > +__init cpuidle_of_cooling_register(struct device_node *np, > + struct cpuidle_driver *drv) > +{ > + struct idle_inject_device *ii_dev; > + struct cpuidle_cooling_device *idle_cdev; > + struct thermal_cooling_device *cdev; > + char dev_name[THERMAL_NAME_LENGTH]; > + int id, ret; > + > + ii_dev = idle_inject_register(drv->cpumask); > + if (IS_ERR(ii_dev)) { > + ret = PTR_ERR(ii_dev); > + goto out; > + } > + I am not sure what's the best way of doing this, but I would have done this after allocating idle_cdev and id. > + idle_cdev = kzalloc(sizeof(*idle_cdev), GFP_KERNEL); > + if (!idle_cdev) { > + ret = -ENOMEM; > + goto out_unregister; > + } > + > + id = ida_simple_get(&cpuidle_ida, 0, 0, GFP_KERNEL); > + if (id < 0) { > + ret = id; > + goto out_kfree; > + } > + > + idle_cdev->ii_dev = ii_dev; > + idle_cdev->idle_duration_us = TICK_USEC; > + > + snprintf(dev_name, sizeof(dev_name), "thermal-idle-%d", id); > + > + cdev = thermal_of_cooling_device_register(np, dev_name, idle_cdev, > + &cpuidle_cooling_ops); > + if (IS_ERR(cdev)) { > + ret = PTR_ERR(cdev); > + goto out_id; > + } > + > + return cdev; > +out_id: > + ida_simple_remove(&cpuidle_ida, id); > +out_kfree: > + kfree(idle_cdev); > +out_unregister: > + idle_inject_unregister(ii_dev); > +out: > + return ERR_PTR(ret); > +} > + > +/** > + * cpuidle_cooling_register - Idle cooling device initialization function > + * @drv: a cpuidle driver structure pointer > + * > + * This function is in charge of creating a cooling device per cpuidle > + * driver and register it to thermal framework. > + * > + * Returns a valid pointer to a thermal cooling device, a PTR_ERR > + * corresponding to the error detected in the underlying subsystems. > + */ > +struct thermal_cooling_device * > +__init cpuidle_cooling_register(struct cpuidle_driver *drv) > +{ > + return cpuidle_of_cooling_register(NULL, drv); > +} > diff --git a/include/linux/cpu_cooling.h b/include/linux/cpu_cooling.h > index 3cdd85f987d7..7873ac2f740b 100644 > --- a/include/linux/cpu_cooling.h > +++ b/include/linux/cpu_cooling.h > @@ -60,4 +60,26 @@ of_cpufreq_cooling_register(struct cpufreq_policy *policy) > } > #endif /* CONFIG_CPU_FREQ_THERMAL */ > > +struct cpuidle_driver; > + > +#ifdef CONFIG_CPU_IDLE_THERMAL > +extern struct thermal_cooling_device * > +__init cpuidle_cooling_register(struct cpuidle_driver *drv); > +extern struct thermal_cooling_device * > +__init cpuidle_of_cooling_register(struct device_node *np, > + struct cpuidle_driver *drv); > +#else /* CONFIG_CPU_IDLE_THERMAL */ > +static inline struct thermal_cooling_device * > +__init cpuidle_cooling_register(struct cpuidle_driver *drv) > +{ > + return ERR_PTR(-EINVAL); > +} > +extern struct thermal_cooling_device * > +__init cpuidle_of_cooling_register(struct device_node *np, > + struct cpuidle_driver *drv) > +{ > + return ERR_PTR(-EINVAL); > +} > +#endif /* CONFIG_CPU_IDLE_THERMAL */ > + > #endif /* __CPU_COOLING_H__ */ > -- > 2.17.1 -- viresh