Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1751946AbdGGQBd (ORCPT ); Fri, 7 Jul 2017 12:01:33 -0400 Received: from foss.arm.com ([217.140.101.70]:48926 "EHLO foss.arm.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1750882AbdGGQBc (ORCPT ); Fri, 7 Jul 2017 12:01:32 -0400 Subject: Re: [PATCH v2 02/10] cpufreq: provide data for frequency-invariant load-tracking support To: Viresh Kumar Cc: linux-kernel@vger.kernel.org, linux-pm@vger.kernel.org, linux@arm.linux.org.uk, Greg Kroah-Hartman , Russell King , Catalin Marinas , Will Deacon , Juri Lelli , Vincent Guittot , Peter Zijlstra , Morten Rasmussen , "Rafael J . Wysocki" References: <20170706094948.8779-1-dietmar.eggemann@arm.com> <20170706094948.8779-3-dietmar.eggemann@arm.com> <20170706104027.GB13048@vireshk-i7> From: Dietmar Eggemann Message-ID: Date: Fri, 7 Jul 2017 17:01:28 +0100 User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:52.0) Gecko/20100101 Thunderbird/52.1.1 MIME-Version: 1.0 In-Reply-To: <20170706104027.GB13048@vireshk-i7> Content-Type: text/plain; charset=utf-8 Content-Language: en-GB Content-Transfer-Encoding: 7bit Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 5001 Lines: 137 On 06/07/17 11:40, Viresh Kumar wrote: > On 06-07-17, 10:49, Dietmar Eggemann wrote: [...] >> In case arch_set_freq_scale() is not defined (and because of the >> pr_debug() drivers/cpufreq/cpufreq.c is not compiled with -DDEBUG) > > The line within () needs to be improved to convey a clear message. Probably not needed anymore. See below. [...] >> diff --git a/drivers/cpufreq/cpufreq.c b/drivers/cpufreq/cpufreq.c >> index 9bf97a366029..a04c5886a5ce 100644 >> --- a/drivers/cpufreq/cpufreq.c >> +++ b/drivers/cpufreq/cpufreq.c >> @@ -347,6 +347,28 @@ static void __cpufreq_notify_transition(struct cpufreq_policy *policy, >> } >> } >> >> +/********************************************************************* >> + * FREQUENCY INVARIANT CPU CAPACITY SUPPORT * >> + *********************************************************************/ >> + >> +#ifndef arch_set_freq_scale >> +static void arch_set_freq_scale(struct cpumask *cpus, unsigned long cur_freq, >> + unsigned long max_freq) >> +{} >> +#endif >> + >> +static void cpufreq_set_freq_scale(struct cpufreq_policy *policy, >> + struct cpufreq_freqs *freqs) >> +{ >> + unsigned long cur_freq = freqs ? freqs->new : policy->cur; >> + unsigned long max_freq = policy->cpuinfo.max_freq; >> + >> + pr_debug("cpus %*pbl cur/cur max freq %lu/%lu kHz\n", >> + cpumask_pr_args(policy->related_cpus), cur_freq, max_freq); >> + >> + arch_set_freq_scale(policy->related_cpus, cur_freq, max_freq); > > I am not sure why all these are required to be sent here and will come back to > it later on after going through other patches. See below. >> +} >> + >> /** >> * cpufreq_notify_transition - call notifier chain and adjust_jiffies >> * on frequency transition. >> @@ -405,6 +427,8 @@ void cpufreq_freq_transition_begin(struct cpufreq_policy *policy, >> >> spin_unlock(&policy->transition_lock); >> >> + cpufreq_set_freq_scale(policy, freqs); >> + > > Why do this before even changing the frequency ? We may fail while changing it. > > IMHO, you should call this routine whenever we update policy->cur and that > happens regularly in __cpufreq_notify_transition() and few other places.. See below. >> cpufreq_notify_transition(policy, freqs, CPUFREQ_PRECHANGE); >> } >> EXPORT_SYMBOL_GPL(cpufreq_freq_transition_begin); >> @@ -2203,6 +2227,8 @@ static int cpufreq_set_policy(struct cpufreq_policy *policy, >> blocking_notifier_call_chain(&cpufreq_policy_notifier_list, >> CPUFREQ_NOTIFY, new_policy); >> >> + cpufreq_set_freq_scale(new_policy, NULL); > > Why added it here ? To get it initialized ? If yes, then we should do that in > cpufreq_online() where we first initialize policy->cur. I agree. This can go away. Initialization is not really needed here. We initialize the scale values to SCHED_CAPACITY_SCALE at boot-time. > Apart from this, you also need to update this in the schedutil governor (if you > haven't done that in this series later) as that also updates policy->cur in the > fast path. So what about I call arch_set_freq_scale() in __cpufreq_notify_transition() in the CPUFREQ_POSTCHANGE case for slow-switching and in cpufreq_driver_fast_switch() for fast-switching? Like this: (only slow-path slightly tested): diff --git a/drivers/cpufreq/cpufreq.c b/drivers/cpufreq/cpufreq.c index 9bf97a366029..77c4d5e7a598 100644 --- a/drivers/cpufreq/cpufreq.c +++ b/drivers/cpufreq/cpufreq.c @@ -301,6 +301,12 @@ static void adjust_jiffies(unsigned long val, struct cpufreq_freqs *ci) #endif } +#ifndef arch_set_freq_scale +static void arch_set_freq_scale(struct cpumask *cpus, unsigned long cur_freq, + unsigned long max_freq) +{} +#endif + static void __cpufreq_notify_transition(struct cpufreq_policy *policy, struct cpufreq_freqs *freqs, unsigned int state) { @@ -343,6 +349,8 @@ static void __cpufreq_notify_transition(struct cpufreq_policy *policy, CPUFREQ_POSTCHANGE, freqs); if (likely(policy) && likely(policy->cpu == freqs->cpu)) policy->cur = freqs->new; + arch_set_freq_scale(policy->related_cpus, policy->cur, + policy->cpuinfo.max_freq); break; } } @@ -1824,9 +1832,18 @@ EXPORT_SYMBOL(cpufreq_unregister_notifier); unsigned int cpufreq_driver_fast_switch(struct cpufreq_policy *policy, unsigned int target_freq) { + unsigned int ret; + target_freq = clamp_val(target_freq, policy->min, policy->max); - return cpufreq_driver->fast_switch(policy, target_freq); + ret = cpufreq_driver->fast_switch(policy, target_freq); + + if (ret != CPUFREQ_ENTRY_INVALID) { + arch_set_freq_scale(policy->related_cpus, target_freq, + policy->cpuinfo.max_freq); + } + + return ret; } EXPORT_SYMBOL_GPL(cpufreq_driver_fast_switch);