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ANDROID: implement max frequency capping

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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: Ionela Voinescu <ionela.voinescu@arm.com>
Signed-off-by: Dietmar Eggemann <dietmar.eggemann@arm.com>
[Trivial cherry-pick issue in cpufreq.c]
Signed-off-by: Quentin Perret <quentin.perret@arm.com>
Change-Id: I59e52861ee260755ab0518fe1f7183a2e4e3d0fc
This commit is contained in:
Dietmar Eggemann
2018-05-10 16:52:33 +01:00
committed by Quentin Perret
parent 6c401bf9b0
commit c4ed8aa44d
4 changed files with 42 additions and 1 deletions
Download Patch File Download Diff File Expand all files Collapse all files

25
drivers/base/arch_topology.c
View File

@@ -18,6 +18,8 @@
#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)
@@ -27,8 +29,29 @@ 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);

8
drivers/cpufreq/cpufreq.c
View File

@@ -159,6 +159,12 @@ __weak void arch_set_freq_scale(struct cpumask *cpus, unsigned long cur_freq,
}
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);
/*
* This is a generic cpufreq init() routine which can be used by cpufreq
* drivers of SMP systems. It will do following:
@@ -2244,6 +2250,8 @@ static int cpufreq_set_policy(struct cpufreq_policy *policy,
policy->max = new_policy->max;
trace_cpu_frequency_limits(policy);
arch_set_max_freq_scale(policy->cpus, policy->max);
policy->cached_target_freq = UINT_MAX;
pr_debug("new min and max freqs are %u - %u kHz\n",

8
include/linux/arch_topology.h
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@@ -33,4 +33,12 @@ unsigned long topology_get_freq_scale(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_ */

2
include/linux/cpufreq.h
View File

@@ -955,6 +955,8 @@ 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;