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Commit b6a1f3e4 authored by Dietmar Eggemann's avatar Dietmar Eggemann Committed by Ionela Voinescu
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ANDROID: implement max frequency capping 



Implements the Max Frequency Capping Engine (MFCE) getter function
topology_get_max_freq_scale() to provide the scheduler with a
maximum frequency scaling correction factor for more accurate cpu
capacity handling by being able to deal with max frequency capping.

This scaling factor describes the influence of running a cpu with a
current maximum frequency (policy) lower than the maximum possible
frequency (cpuinfo).

The factor is:

  policy_max_freq(cpu) << SCHED_CAPACITY_SHIFT / cpuinfo_max_freq(cpu)

It also implements the MFCE setter function arch_set_max_freq_scale()
which is called from cpufreq_set_policy().

Signed-off-by: default avatarDietmar Eggemann <dietmar.eggemann@arm.com>
Signed-off-by: default avatarIonela Voinescu <ionela.voinescu@arm.com>
Change-Id: I59e52861ee260755ab0518fe1f7183a2e4e3d0fc
parent 44791a47

drivers/base/arch_topology.c

+24 −1
Original line number Diff line number Diff line
@@ -25,6 +25,8 @@ 
#include <linux/cpuset.h>



DEFINE_PER_CPU(unsigned long, freq_scale) = SCHED_CAPACITY_SCALE;

DEFINE_PER_CPU(unsigned long, max_cpu_freq);

DEFINE_PER_CPU(unsigned long, max_freq_scale) = SCHED_CAPACITY_SCALE;



void arch_set_freq_scale(struct cpumask *cpus, unsigned long cur_freq,

			 unsigned long max_freq)
@@ -34,8 +36,29 @@ void arch_set_freq_scale(struct cpumask *cpus, unsigned long cur_freq, 


	scale = (cur_freq << SCHED_CAPACITY_SHIFT) / max_freq;



	for_each_cpu(i, cpus)

	for_each_cpu(i, cpus) {

		per_cpu(freq_scale, i) = scale;

		per_cpu(max_cpu_freq, i) = max_freq;

	}

}



void arch_set_max_freq_scale(struct cpumask *cpus,

			     unsigned long policy_max_freq)

{

	unsigned long scale, max_freq;

	int cpu = cpumask_first(cpus);



	if (cpu > nr_cpu_ids)

		return;



	max_freq = per_cpu(max_cpu_freq, cpu);

	if (!max_freq)

		return;



	scale = (policy_max_freq << SCHED_CAPACITY_SHIFT) / max_freq;



	for_each_cpu(cpu, cpus)

		per_cpu(max_freq_scale, cpu) = scale;

}



static DEFINE_MUTEX(cpu_scale_mutex);

drivers/cpufreq/cpufreq.c

+9 −0
Original line number Diff line number Diff line
@@ -2237,6 +2237,9 @@ static int cpufreq_set_policy(struct cpufreq_policy *policy, 


	policy->min = new_policy->min;

	policy->max = new_policy->max;



	arch_set_max_freq_scale(policy->cpus, policy->max);



	trace_cpu_frequency_limits(policy->max, policy->min, policy->cpu);



	policy->cached_target_freq = UINT_MAX;
@@ -2447,6 +2450,12 @@ __weak void arch_set_freq_scale(struct cpumask *cpus, 
}

EXPORT_SYMBOL_GPL(arch_set_freq_scale);



__weak void arch_set_max_freq_scale(struct cpumask *cpus,

				    unsigned long policy_max_freq)

{

}

EXPORT_SYMBOL_GPL(arch_set_max_freq_scale);



/*********************************************************************

 *               REGISTER / UNREGISTER CPUFREQ DRIVER                *

 *********************************************************************/

include/linux/arch_topology.h

+8 −0
Original line number Diff line number Diff line
@@ -37,4 +37,12 @@ unsigned long topology_get_freq_scale(struct sched_domain *sd, int cpu) 
	return per_cpu(freq_scale, cpu);

}



DECLARE_PER_CPU(unsigned long, max_freq_scale);



static inline

unsigned long topology_get_max_freq_scale(struct sched_domain *sd, int cpu)

{

	return per_cpu(max_freq_scale, cpu);

}



#endif /* _LINUX_ARCH_TOPOLOGY_H_ */

include/linux/cpufreq.h

+2 −0
Original line number Diff line number Diff line
@@ -922,6 +922,8 @@ extern unsigned int arch_freq_get_on_cpu(int cpu); 


extern void arch_set_freq_scale(struct cpumask *cpus, unsigned long cur_freq,

				unsigned long max_freq);

extern void arch_set_max_freq_scale(struct cpumask *cpus,

				    unsigned long policy_max_freq);



/* the following are really really optional */

extern struct freq_attr cpufreq_freq_attr_scaling_available_freqs;