diff mbox series

[V2,1/9] cpufreq: Auto-register with energy model if asked

Message ID 9ca302a02d6b51240af8668634c93972183b593f.1628682874.git.viresh.kumar@linaro.org
State New
Headers show
Series cpufreq: Auto-register with energy model | expand

Commit Message

Viresh Kumar Aug. 11, 2021, 11:58 a.m. UTC
Many cpufreq drivers register with the energy model for each policy and
do exactly the same thing. Follow the footsteps of thermal-cooling, to
get it done from the cpufreq core itself.

Provide a new callback, which will be called, if present, by the cpufreq
core at the right moment (more on that in the code's comment). Also
provide a generic implementation that uses dev_pm_opp_of_register_em().

This also allows us to register with the EM at a later point of time,
compared to ->init(), from where the EM core can access cpufreq policy
directly using cpufreq_cpu_get() type of helpers and perform other work,
like marking few frequencies inefficient, this will be done separately.

Signed-off-by: Viresh Kumar <viresh.kumar@linaro.org>

---
 drivers/cpufreq/cpufreq.c | 12 ++++++++++++
 include/linux/cpufreq.h   | 14 ++++++++++++++
 2 files changed, 26 insertions(+)

-- 
2.31.1.272.g89b43f80a514

Comments

Quentin Perret Aug. 11, 2021, 1:02 p.m. UTC | #1
On Wednesday 11 Aug 2021 at 17:28:39 (+0530), Viresh Kumar wrote:
> Many cpufreq drivers register with the energy model for each policy and

> do exactly the same thing. Follow the footsteps of thermal-cooling, to

> get it done from the cpufreq core itself.

> 

> Provide a new callback, which will be called, if present, by the cpufreq

> core at the right moment (more on that in the code's comment). Also

> provide a generic implementation that uses dev_pm_opp_of_register_em().

> 

> This also allows us to register with the EM at a later point of time,

> compared to ->init(), from where the EM core can access cpufreq policy

> directly using cpufreq_cpu_get() type of helpers and perform other work,

> like marking few frequencies inefficient, this will be done separately.

> 

> Signed-off-by: Viresh Kumar <viresh.kumar@linaro.org>

> ---

>  drivers/cpufreq/cpufreq.c | 12 ++++++++++++

>  include/linux/cpufreq.h   | 14 ++++++++++++++

>  2 files changed, 26 insertions(+)

> 

> diff --git a/drivers/cpufreq/cpufreq.c b/drivers/cpufreq/cpufreq.c

> index 06c526d66dd3..75974e7d6cc5 100644

> --- a/drivers/cpufreq/cpufreq.c

> +++ b/drivers/cpufreq/cpufreq.c

> @@ -1493,6 +1493,18 @@ static int cpufreq_online(unsigned int cpu)

>  		write_unlock_irqrestore(&cpufreq_driver_lock, flags);

>  	}

>  

> +	/*

> +	 * Register with the energy model before sched_cpufreq_governor_change()

> +	 * is called, which will result in rebuilding of the sched domains,

> +	 * which should only be done once the energy model is properly

> +	 * initialized for the policy first.

> +	 *

> +	 * Also, this should be called before the policy is registered with

> +	 * cooling framework.

> +	 */

> +	if (cpufreq_driver->register_em)

> +		cpufreq_driver->register_em(policy);


Maybe move that to the 'if (new_policy)' block above? There is currently
no need to re-register the EM on CPU hotplug.

>  	ret = cpufreq_init_policy(policy);

>  	if (ret) {

>  		pr_err("%s: Failed to initialize policy for cpu: %d (%d)\n",

> diff --git a/include/linux/cpufreq.h b/include/linux/cpufreq.h

> index 9fd719475fcd..1295621f6c28 100644

> --- a/include/linux/cpufreq.h

> +++ b/include/linux/cpufreq.h

> @@ -9,10 +9,12 @@

>  #define _LINUX_CPUFREQ_H

>  

>  #include <linux/clk.h>

> +#include <linux/cpu.h>

>  #include <linux/cpumask.h>

>  #include <linux/completion.h>

>  #include <linux/kobject.h>

>  #include <linux/notifier.h>

> +#include <linux/pm_opp.h>

>  #include <linux/pm_qos.h>

>  #include <linux/spinlock.h>

>  #include <linux/sysfs.h>

> @@ -373,6 +375,12 @@ struct cpufreq_driver {

>  	/* platform specific boost support code */

>  	bool		boost_enabled;

>  	int		(*set_boost)(struct cpufreq_policy *policy, int state);

> +

> +	/*

> +	 * Set by drivers that want the core to automatically register the

> +	 * policy's devices with Energy Model.

> +	 */

> +	void		(*register_em)(struct cpufreq_policy *policy);

>  };

>  

>  /* flags */

> @@ -1046,4 +1054,10 @@ unsigned int cpufreq_generic_get(unsigned int cpu);

>  void cpufreq_generic_init(struct cpufreq_policy *policy,

>  		struct cpufreq_frequency_table *table,

>  		unsigned int transition_latency);

> +

> +static inline void cpufreq_register_em_with_opp(struct cpufreq_policy *policy)

> +{

> +	dev_pm_opp_of_register_em(get_cpu_device(policy->cpu),

> +				  policy->related_cpus);

> +}


I was thinking this could go in pm_opp.h instead, but it doesn't really
matter.

So, with the first comment above fixed:

Reviewed-by: Quentin Perret <qperret@google.com>


Thanks,
Quentin
Lukasz Luba Aug. 11, 2021, 2:30 p.m. UTC | #2
On 8/11/21 12:58 PM, Viresh Kumar wrote:
> Many cpufreq drivers register with the energy model for each policy and

> do exactly the same thing. Follow the footsteps of thermal-cooling, to

> get it done from the cpufreq core itself.

> 

> Provide a new callback, which will be called, if present, by the cpufreq

> core at the right moment (more on that in the code's comment). Also

> provide a generic implementation that uses dev_pm_opp_of_register_em().

> 

> This also allows us to register with the EM at a later point of time,

> compared to ->init(), from where the EM core can access cpufreq policy

> directly using cpufreq_cpu_get() type of helpers and perform other work,

> like marking few frequencies inefficient, this will be done separately.

> 

> Signed-off-by: Viresh Kumar <viresh.kumar@linaro.org>

> ---

>   drivers/cpufreq/cpufreq.c | 12 ++++++++++++

>   include/linux/cpufreq.h   | 14 ++++++++++++++

>   2 files changed, 26 insertions(+)

> 

> diff --git a/drivers/cpufreq/cpufreq.c b/drivers/cpufreq/cpufreq.c

> index 06c526d66dd3..75974e7d6cc5 100644

> --- a/drivers/cpufreq/cpufreq.c

> +++ b/drivers/cpufreq/cpufreq.c

> @@ -1493,6 +1493,18 @@ static int cpufreq_online(unsigned int cpu)

>   		write_unlock_irqrestore(&cpufreq_driver_lock, flags);

>   	}

>   

> +	/*

> +	 * Register with the energy model before sched_cpufreq_governor_change()

> +	 * is called, which will result in rebuilding of the sched domains,

> +	 * which should only be done once the energy model is properly

> +	 * initialized for the policy first.

> +	 *

> +	 * Also, this should be called before the policy is registered with

> +	 * cooling framework.

> +	 */

> +	if (cpufreq_driver->register_em)

> +		cpufreq_driver->register_em(policy);

> +

>   	ret = cpufreq_init_policy(policy);

>   	if (ret) {

>   		pr_err("%s: Failed to initialize policy for cpu: %d (%d)\n",

> diff --git a/include/linux/cpufreq.h b/include/linux/cpufreq.h

> index 9fd719475fcd..1295621f6c28 100644

> --- a/include/linux/cpufreq.h

> +++ b/include/linux/cpufreq.h

> @@ -9,10 +9,12 @@

>   #define _LINUX_CPUFREQ_H

>   

>   #include <linux/clk.h>

> +#include <linux/cpu.h>

>   #include <linux/cpumask.h>

>   #include <linux/completion.h>

>   #include <linux/kobject.h>

>   #include <linux/notifier.h>

> +#include <linux/pm_opp.h>

>   #include <linux/pm_qos.h>

>   #include <linux/spinlock.h>

>   #include <linux/sysfs.h>

> @@ -373,6 +375,12 @@ struct cpufreq_driver {

>   	/* platform specific boost support code */

>   	bool		boost_enabled;

>   	int		(*set_boost)(struct cpufreq_policy *policy, int state);

> +

> +	/*

> +	 * Set by drivers that want the core to automatically register the

> +	 * policy's devices with Energy Model.


It covers one use case. I would add also something about customized EM
setup, which might be provided by drivers and implemented then in this
callback. It won't be only for automatic registration.


> +	 */

> +	void		(*register_em)(struct cpufreq_policy *policy);

>   };

>   

>   /* flags */

> @@ -1046,4 +1054,10 @@ unsigned int cpufreq_generic_get(unsigned int cpu);

>   void cpufreq_generic_init(struct cpufreq_policy *policy,

>   		struct cpufreq_frequency_table *table,

>   		unsigned int transition_latency);

> +

> +static inline void cpufreq_register_em_with_opp(struct cpufreq_policy *policy)

> +{

> +	dev_pm_opp_of_register_em(get_cpu_device(policy->cpu),

> +				  policy->related_cpus);

> +}

>   #endif /* _LINUX_CPUFREQ_H */

> 


There rest is OK,

Reviewed-by: Lukasz Luba <lukasz.luba@arm.com>
diff mbox series

Patch

diff --git a/drivers/cpufreq/cpufreq.c b/drivers/cpufreq/cpufreq.c
index 06c526d66dd3..75974e7d6cc5 100644
--- a/drivers/cpufreq/cpufreq.c
+++ b/drivers/cpufreq/cpufreq.c
@@ -1493,6 +1493,18 @@  static int cpufreq_online(unsigned int cpu)
 		write_unlock_irqrestore(&cpufreq_driver_lock, flags);
 	}
 
+	/*
+	 * Register with the energy model before sched_cpufreq_governor_change()
+	 * is called, which will result in rebuilding of the sched domains,
+	 * which should only be done once the energy model is properly
+	 * initialized for the policy first.
+	 *
+	 * Also, this should be called before the policy is registered with
+	 * cooling framework.
+	 */
+	if (cpufreq_driver->register_em)
+		cpufreq_driver->register_em(policy);
+
 	ret = cpufreq_init_policy(policy);
 	if (ret) {
 		pr_err("%s: Failed to initialize policy for cpu: %d (%d)\n",
diff --git a/include/linux/cpufreq.h b/include/linux/cpufreq.h
index 9fd719475fcd..1295621f6c28 100644
--- a/include/linux/cpufreq.h
+++ b/include/linux/cpufreq.h
@@ -9,10 +9,12 @@ 
 #define _LINUX_CPUFREQ_H
 
 #include <linux/clk.h>
+#include <linux/cpu.h>
 #include <linux/cpumask.h>
 #include <linux/completion.h>
 #include <linux/kobject.h>
 #include <linux/notifier.h>
+#include <linux/pm_opp.h>
 #include <linux/pm_qos.h>
 #include <linux/spinlock.h>
 #include <linux/sysfs.h>
@@ -373,6 +375,12 @@  struct cpufreq_driver {
 	/* platform specific boost support code */
 	bool		boost_enabled;
 	int		(*set_boost)(struct cpufreq_policy *policy, int state);
+
+	/*
+	 * Set by drivers that want the core to automatically register the
+	 * policy's devices with Energy Model.
+	 */
+	void		(*register_em)(struct cpufreq_policy *policy);
 };
 
 /* flags */
@@ -1046,4 +1054,10 @@  unsigned int cpufreq_generic_get(unsigned int cpu);
 void cpufreq_generic_init(struct cpufreq_policy *policy,
 		struct cpufreq_frequency_table *table,
 		unsigned int transition_latency);
+
+static inline void cpufreq_register_em_with_opp(struct cpufreq_policy *policy)
+{
+	dev_pm_opp_of_register_em(get_cpu_device(policy->cpu),
+				  policy->related_cpus);
+}
 #endif /* _LINUX_CPUFREQ_H */