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=-6.8 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,URIBL_BLOCKED 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 628F3C10F14 for ; Tue, 15 Oct 2019 13:06:45 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id 2268F21848 for ; Tue, 15 Oct 2019 13:06:45 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=pass (2048-bit key) header.d=linaro.org header.i=@linaro.org header.b="rhGTsL53" Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1730620AbfJONGn (ORCPT ); Tue, 15 Oct 2019 09:06:43 -0400 Received: from mail-vs1-f65.google.com ([209.85.217.65]:41824 "EHLO mail-vs1-f65.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1728607AbfJONGn (ORCPT ); Tue, 15 Oct 2019 09:06:43 -0400 Received: by mail-vs1-f65.google.com with SMTP id l2so13054225vsr.8 for ; Tue, 15 Oct 2019 06:06:42 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=linaro.org; s=google; h=mime-version:references:in-reply-to:from:date:message-id:subject:to :cc; bh=rNOlv3NjVeyQoBdu+mBLCof6nCnJjTRih3rxG6wI0Rc=; b=rhGTsL53yetLxs9HbEFP3SVNGZ9WhPPu9ZCP6S56L3oRjry+hL6HOwj6DDwx+fF3IF bwbs7XGCZiyKjvfTtmZIDnYEGTRDiqZwrae6vRyCqpqHfIX8LEtDBDVQcebexP6hs4dq fm0TSVFFlHaFuH4zthVu6co0xNQvYWDyFVHxNrpD03GqZRj5XOV3qBkZJ6iZ0kFdUpzB p2XnlitTTNrN0x/qDI1oWYKBqckkREo271eo58exPHfJ00z3+cLdADTe0zHD2/uvc7co WhaFhkn+ZqSjn9l9+BZJ6iPmf6wHCHXSXG+dp3ibdZtK7LjxlYCAnBmWSDVQItj+vZXP yKew== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20161025; h=x-gm-message-state:mime-version:references:in-reply-to:from:date :message-id:subject:to:cc; bh=rNOlv3NjVeyQoBdu+mBLCof6nCnJjTRih3rxG6wI0Rc=; b=M8I4YBnqaz2slI6f98fxnSzZBAQDAyN92RMxuqFKF0BRAOOnu3qZZ2GbbBEQcTNp4T bDIYUSiXn+/o7v1lT4iV4ytDwvbG8AedjhtOVLWfHppoJNkyG3uanqZwmSe+egY+9rSE dYKfBc9SzyZ8U2gRS8/5GJrGXAtXelVqgVJ6AnxB/HpMeb11V4PQjpdZkIEc830e3oTR YMh7lCXSLEuWc/N2Cc/A13QR1hHUS8NrUb1JFM9OY8Ly1ny4KVrp4r+KAw7tWcPejN3f oKgrmyvQIghHk81aiOHvqr57x6DsldL5Lr9ooVdvc/y1M0/bz0a0RSgpVZ0HZXISamsz V0Ug== X-Gm-Message-State: APjAAAUtrZkimyVFEMGHMK4DpBscvGcAbgm79T1nQobVXwJqaZFy4zdS 7Ka2SGk2imGDsBb9J77zPFO/93uhZizfUw61L9J/3w== X-Google-Smtp-Source: APXvYqypVfUGTpAza4VLnzEyKjqobPPXW581gBdi2BYaMn0ijCdmNFl+uKP1xChRfG9KdmJKJ2jsBna1yMSk93SxYOY= X-Received: by 2002:a67:ef89:: with SMTP id r9mr20648010vsp.200.1571144801705; Tue, 15 Oct 2019 06:06:41 -0700 (PDT) MIME-Version: 1.0 References: <20191004083205.29302-1-daniel.lezcano@linaro.org> In-Reply-To: <20191004083205.29302-1-daniel.lezcano@linaro.org> From: Ulf Hansson Date: Tue, 15 Oct 2019 15:06:04 +0200 Message-ID: Subject: Re: [PATCH V4 1/3] cpuidle: play_idle: Make play_idle more flexible To: Daniel Lezcano Cc: "Rafael J. Wysocki" , Mathieu Poirier , Ingo Molnar , Peter Zijlstra , "open list:CPU IDLE TIME MANAGEMENT FRAMEWORK" , open list Content-Type: text/plain; charset="UTF-8" Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Fri, 4 Oct 2019 at 10:32, Daniel Lezcano wrote: > > The play_idle function has two users, the intel powerclamp and the > idle_injection. > > The idle injection cooling device uses the function via the > idle_injection powercap's APIs. Unfortunately, play_idle is currently > limited by the idle state depth: by default the deepest idle state is > selected. On the ARM[64] platforms, most of the time it is the cluster > idle state, the exit latency and the residency can be very high. That > reduces the scope of the idle injection usage because the impact on > the performances can be very significant. > > If the idle injection cycles can be done with a shallow state like a > retention state, the cooling effect would eventually give similar > results than the cpufreq cooling device. > > In order to prepare the function to receive an idle state parameter, > let's replace the 'use_deepest_state' boolean field with 'use_state' > and use this value to enter the specific idle state. > > The current code keeps the default behavior which is go to the deepest > idle state. > > Signed-off-by: Daniel Lezcano > Acked-by: Mathieu Poirier > --- > drivers/cpuidle/cpuidle.c | 21 +++++++++++---------- > include/linux/cpuidle.h | 13 ++++++------- > kernel/sched/idle.c | 10 +++++----- > 3 files changed, 22 insertions(+), 22 deletions(-) > > diff --git a/drivers/cpuidle/cpuidle.c b/drivers/cpuidle/cpuidle.c > index 0895b988fa92..f8b54f277589 100644 > --- a/drivers/cpuidle/cpuidle.c > +++ b/drivers/cpuidle/cpuidle.c > @@ -99,31 +99,31 @@ static int find_deepest_state(struct cpuidle_driver *drv, > } > > /** > - * cpuidle_use_deepest_state - Set/clear governor override flag. > - * @enable: New value of the flag. > + * cpuidle_use_state - Force the cpuidle framework to enter an idle state. > + * @state: An integer for an idle state > * > - * Set/unset the current CPU to use the deepest idle state (override governors > - * going forward if set). > + * Specify an idle state the cpuidle framework must step in and bypass > + * the idle state selection process. > */ > -void cpuidle_use_deepest_state(bool enable) > +void cpuidle_use_state(int state) > { > struct cpuidle_device *dev; > > preempt_disable(); > dev = cpuidle_get_device(); > if (dev) > - dev->use_deepest_state = enable; > + dev->use_state = state; > preempt_enable(); > } > > /** > * cpuidle_find_deepest_state - Find the deepest available idle state. > - * @drv: cpuidle driver for the given CPU. > - * @dev: cpuidle device for the given CPU. > */ > -int cpuidle_find_deepest_state(struct cpuidle_driver *drv, > - struct cpuidle_device *dev) > +int cpuidle_find_deepest_state(void) > { > + struct cpuidle_device *dev = cpuidle_get_device(); > + struct cpuidle_driver *drv = cpuidle_get_cpu_driver(dev); > + > return find_deepest_state(drv, dev, UINT_MAX, 0, false); > } > > @@ -554,6 +554,7 @@ static void __cpuidle_unregister_device(struct cpuidle_device *dev) > static void __cpuidle_device_init(struct cpuidle_device *dev) > { > memset(dev->states_usage, 0, sizeof(dev->states_usage)); > + dev->use_state = CPUIDLE_STATE_NOUSE; > dev->last_residency = 0; > dev->next_hrtimer = 0; > } > diff --git a/include/linux/cpuidle.h b/include/linux/cpuidle.h > index 2dc4c6b19c25..ba0751b26e37 100644 > --- a/include/linux/cpuidle.h > +++ b/include/linux/cpuidle.h > @@ -15,6 +15,7 @@ > #include > #include > > +#define CPUIDLE_STATE_NOUSE -1 > #define CPUIDLE_STATE_MAX 10 > #define CPUIDLE_NAME_LEN 16 > #define CPUIDLE_DESC_LEN 32 > @@ -80,11 +81,11 @@ struct cpuidle_driver_kobj; > struct cpuidle_device { > unsigned int registered:1; > unsigned int enabled:1; > - unsigned int use_deepest_state:1; > unsigned int poll_time_limit:1; > unsigned int cpu; > ktime_t next_hrtimer; > > + int use_state; > int last_state_idx; > int last_residency; > u64 poll_limit_ns; > @@ -203,19 +204,17 @@ static inline struct cpuidle_device *cpuidle_get_device(void) {return NULL; } > #endif > > #ifdef CONFIG_CPU_IDLE > -extern int cpuidle_find_deepest_state(struct cpuidle_driver *drv, > - struct cpuidle_device *dev); > +extern int cpuidle_find_deepest_state(void); > extern int cpuidle_enter_s2idle(struct cpuidle_driver *drv, > struct cpuidle_device *dev); > -extern void cpuidle_use_deepest_state(bool enable); > +extern void cpuidle_use_state(int state); > #else > -static inline int cpuidle_find_deepest_state(struct cpuidle_driver *drv, > - struct cpuidle_device *dev) > +static inline int cpuidle_find_deepest_state(void) > {return -ENODEV; } > static inline int cpuidle_enter_s2idle(struct cpuidle_driver *drv, > struct cpuidle_device *dev) > {return -ENODEV; } > -static inline void cpuidle_use_deepest_state(bool enable) > +static inline void cpuidle_use_state(int state) > { > } > #endif > diff --git a/kernel/sched/idle.c b/kernel/sched/idle.c > index b98283fc6914..17da9cb309e1 100644 > --- a/kernel/sched/idle.c > +++ b/kernel/sched/idle.c > @@ -165,7 +165,8 @@ static void cpuidle_idle_call(void) > * until a proper wakeup interrupt happens. > */ > > - if (idle_should_enter_s2idle() || dev->use_deepest_state) { > + if (idle_should_enter_s2idle() || > + dev->use_state != CPUIDLE_STATE_NOUSE) { > if (idle_should_enter_s2idle()) { > rcu_idle_enter(); > > @@ -181,8 +182,7 @@ static void cpuidle_idle_call(void) > tick_nohz_idle_stop_tick(); > rcu_idle_enter(); > > - next_state = cpuidle_find_deepest_state(drv, dev); > - call_cpuidle(drv, dev, next_state); > + call_cpuidle(drv, dev, dev->use_state); This doesn't look correct to me. More precisely, in the s2idle case, we always pick the deepest state. But from the change above, we would invoke call_cpuidle() with CPUIDLE_STATE_NOUSE, right!? > } else { > bool stop_tick = true; > > @@ -328,7 +328,7 @@ void play_idle(unsigned long duration_us) > rcu_sleep_check(); > preempt_disable(); > current->flags |= PF_IDLE; > - cpuidle_use_deepest_state(true); > + cpuidle_use_state(cpuidle_find_deepest_state()); > > it.done = 0; > hrtimer_init_on_stack(&it.timer, CLOCK_MONOTONIC, HRTIMER_MODE_REL); > @@ -339,7 +339,7 @@ void play_idle(unsigned long duration_us) > while (!READ_ONCE(it.done)) > do_idle(); > > - cpuidle_use_deepest_state(false); > + cpuidle_use_state(CPUIDLE_STATE_NOUSE); > current->flags &= ~PF_IDLE; > > preempt_fold_need_resched(); > -- > 2.17.1 > Kind regards Uffe