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From: Quentin Perret <quentin.perret@arm.com>
To: Matthias Kaehlcke <mka@chromium.org>
Cc: peterz@infradead.org, rjw@rjwysocki.net,
	linux-kernel@vger.kernel.org, linux-pm@vger.kernel.org,
	gregkh@linuxfoundation.org, mingo@redhat.com,
	dietmar.eggemann@arm.com, morten.rasmussen@arm.com,
	chris.redpath@arm.com, patrick.bellasi@arm.com,
	valentin.schneider@arm.com, vincent.guittot@linaro.org,
	thara.gopinath@linaro.org, viresh.kumar@linaro.org,
	tkjos@google.com, joel@joelfernandes.org, smuckle@google.com,
	adharmap@codeaurora.org, skannan@codeaurora.org,
	pkondeti@codeaurora.org, juri.lelli@redhat.com,
	edubezval@gmail.com, srinivas.pandruvada@linux.intel.com,
	currojerez@riseup.net, javi.merino@kernel.org
Subject: Re: [PATCH v10 15/15] OPTIONAL: cpufreq: dt: Register an Energy Model
Date: Wed, 9 Jan 2019 10:57:57 +0000	[thread overview]
Message-ID: <20190109105757.2rowxn3anzyycuod@queper01-lin> (raw)
In-Reply-To: <20190108203813.GS261387@google.com>

Hi Matthias ,

On Tuesday 08 Jan 2019 at 12:38:13 (-0800), Matthias Kaehlcke wrote:
> >  static int cpufreq_init(struct cpufreq_policy *policy)
> >  {
> > +	struct em_data_callback em_cb = EM_DATA_CB(of_est_power);
> >  	struct cpufreq_frequency_table *freq_table;
> >  	struct opp_table *opp_table = NULL;
> >  	struct private_data *priv;
> > @@ -160,7 +203,7 @@ static int cpufreq_init(struct cpufreq_policy *policy)
> >  	unsigned int transition_latency;
> >  	bool fallback = false;
> >  	const char *name;
> > -	int ret;
> > +	int ret, nr_opp;
> >  
> >  	cpu_dev = get_cpu_device(policy->cpu);
> >  	if (!cpu_dev) {
> > @@ -237,6 +280,7 @@ static int cpufreq_init(struct cpufreq_policy *policy)
> >  		ret = -EPROBE_DEFER;
> >  		goto out_free_opp;
> >  	}
> > +	nr_opp = ret;
> >  
> >  	if (fallback) {
> >  		cpumask_setall(policy->cpus);
> > @@ -280,6 +324,8 @@ static int cpufreq_init(struct cpufreq_policy *policy)
> >  	policy->cpuinfo.transition_latency = transition_latency;
> >  	policy->dvfs_possible_from_any_cpu = true;
> >  
> > +	em_register_perf_domain(policy->cpus, nr_opp, &em_cb);
> 
> Shouldn't there also be a function to unregister a perf domain to be
> called from cpufreq_exit()?
> 
> ->exit() is called on suspend when the CPUs are taken offline, and
> ->init() on resume, hence em_register_perf_domain() is called multiple
> times, but without doing any cleanup.

Right, but this is safe to do as em_register_perf_domain() checks for
the existence of the domain straight away. So the second time you call
this em_register_perf_domain() should just bail out. Are you seeing an
issue with this ?

As of now, the EM framework is really simple -- it justs allocates the
pd tables once during boot, and they stay in memory forever. While
arguably less than optimal, that makes things a whole lot easier to
manage on the client side (i.e. the scheduler) w/o needing RCU
protection or so.

Thanks,
Quentin

  reply	other threads:[~2019-01-09 10:58 UTC|newest]

Thread overview: 45+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2018-12-03  9:56 [PATCH v10 00/15] Energy Aware Scheduling Quentin Perret
2018-12-03  9:56 ` [PATCH v10 01/15] sched: Relocate arch_scale_cpu_capacity Quentin Perret
2018-12-11 15:32   ` [tip:sched/core] sched/topology: Relocate arch_scale_cpu_capacity() to the internal header tip-bot for Quentin Perret
2018-12-03  9:56 ` [PATCH v10 02/15] sched/cpufreq: Prepare schedutil for Energy Aware Scheduling Quentin Perret
2018-12-11 12:01   ` Rafael J. Wysocki
2018-12-11 12:17     ` Quentin Perret
2018-12-11 12:22       ` Rafael J. Wysocki
2018-12-11 12:24         ` Quentin Perret
2018-12-11 15:33   ` [tip:sched/core] " tip-bot for Quentin Perret
2018-12-03  9:56 ` [PATCH v10 03/15] PM: Introduce an Energy Model management framework Quentin Perret
2018-12-11 15:33   ` [tip:sched/core] " tip-bot for Quentin Perret
2018-12-03  9:56 ` [PATCH v10 04/15] PM / EM: Expose the Energy Model in sysfs Quentin Perret
2018-12-11 14:18   ` Ingo Molnar
2018-12-11 15:04     ` Quentin Perret
2018-12-03  9:56 ` [PATCH v10 05/15] sched/topology: Reference the Energy Model of CPUs when available Quentin Perret
2018-12-11 15:34   ` [tip:sched/core] " tip-bot for Quentin Perret
2018-12-03  9:56 ` [PATCH v10 06/15] sched/topology: Lowest CPU asymmetry sched_domain level pointer Quentin Perret
2018-12-11 15:34   ` [tip:sched/core] sched/topology: Add lowest " tip-bot for Quentin Perret
2018-12-03  9:56 ` [PATCH v10 07/15] sched/topology: Disable EAS on inappropriate platforms Quentin Perret
2018-12-11 15:35   ` [tip:sched/core] " tip-bot for Quentin Perret
2018-12-03  9:56 ` [PATCH v10 08/15] sched/topology: Make Energy Aware Scheduling depend on schedutil Quentin Perret
2018-12-11 15:36   ` [tip:sched/core] " tip-bot for Quentin Perret
2018-12-03  9:56 ` [PATCH v10 09/15] sched: Introduce sched_energy_present static key Quentin Perret
2018-12-11 15:36   ` [tip:sched/core] sched/toplogy: Introduce the 'sched_energy_present' " tip-bot for Quentin Perret
2018-12-13 13:56     ` Quentin Perret
2018-12-03  9:56 ` [PATCH v10 10/15] sched: Introduce a sysctl for Energy Aware Scheduling Quentin Perret
2018-12-11 14:15   ` Ingo Molnar
2018-12-11 14:49     ` Quentin Perret
2018-12-13 14:03       ` Peter Zijlstra
2019-01-21 11:35   ` [tip:sched/core] sched/topology: " tip-bot for Quentin Perret
2019-01-21 13:51   ` tip-bot for Quentin Perret
2019-01-27 11:34   ` tip-bot for Quentin Perret
2018-12-03  9:56 ` [PATCH v10 11/15] sched/fair: Clean-up update_sg_lb_stats parameters Quentin Perret
2018-12-11 15:37   ` [tip:sched/core] " tip-bot for Quentin Perret
2018-12-03  9:56 ` [PATCH v10 12/15] sched: Add over-utilization/tipping point indicator Quentin Perret
2018-12-11 15:37   ` [tip:sched/core] sched/fair: " tip-bot for Morten Rasmussen
2018-12-03  9:56 ` [PATCH v10 13/15] sched/fair: Introduce an energy estimation helper function Quentin Perret
2018-12-11 15:38   ` [tip:sched/core] " tip-bot for Quentin Perret
2018-12-03  9:56 ` [PATCH v10 14/15] sched/fair: Select an energy-efficient CPU on task wake-up Quentin Perret
2018-12-11 15:39   ` [tip:sched/core] " tip-bot for Quentin Perret
2018-12-03  9:56 ` [PATCH v10 15/15] OPTIONAL: cpufreq: dt: Register an Energy Model Quentin Perret
2019-01-08 20:38   ` Matthias Kaehlcke
2019-01-09 10:57     ` Quentin Perret [this message]
2019-01-09 18:14       ` Matthias Kaehlcke
2019-01-10  9:08         ` Quentin Perret

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