cpufreq: implement max frequency capping
Implements the Max Frequency Capping Engine (MFCE) getter function
cpufreq_scale_max_freq_capacity() 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 scale_max_freq_capacity()
which is called from cpufreq_set_policy().
Change-Id: I38ef736cfa587520cf4f97012be25cbb0c5af04d
Signed-off-by: Dietmar Eggemann <dietmar.eggemann@arm.com>
Signed-off-by: Chris Redpath <chris.redpath@arm.com>
Git-commit: 7b619defb7bb44a5f0ab9c68b1d902e0e7db468c
Git-repo: https://android.googlesource.com/kernel/common/
Signed-off-by: Pavankumar Kondeti <pkondeti@codeaurora.org>
diff --git a/drivers/cpufreq/cpufreq.c b/drivers/cpufreq/cpufreq.c
index b0aebe3..9b42404 100644
--- a/drivers/cpufreq/cpufreq.c
+++ b/drivers/cpufreq/cpufreq.c
@@ -325,6 +325,8 @@
*********************************************************************/
static DEFINE_PER_CPU(unsigned long, freq_scale) = SCHED_CAPACITY_SCALE;
+static DEFINE_PER_CPU(unsigned long, max_freq_cpu);
+static DEFINE_PER_CPU(unsigned long, max_freq_scale) = SCHED_CAPACITY_SCALE;
static void
scale_freq_capacity(const cpumask_t *cpus, unsigned long cur_freq,
@@ -333,8 +335,10 @@
unsigned long scale = (cur_freq << SCHED_CAPACITY_SHIFT) / max_freq;
int cpu;
- for_each_cpu(cpu, cpus)
+ for_each_cpu(cpu, cpus) {
per_cpu(freq_scale, cpu) = scale;
+ per_cpu(max_freq_cpu, cpu) = max_freq;
+ }
pr_debug("cpus %*pbl cur freq/max freq %lu/%lu kHz freq scale %lu\n",
cpumask_pr_args(cpus), cur_freq, max_freq, scale);
@@ -345,6 +349,34 @@
return per_cpu(freq_scale, cpu);
}
+static void
+scale_max_freq_capacity(const cpumask_t *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_freq_cpu, 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;
+
+ pr_debug("cpus %*pbl policy max freq/max freq %lu/%lu kHz max freq scale %lu\n",
+ cpumask_pr_args(cpus), policy_max_freq, max_freq, scale);
+}
+
+unsigned long cpufreq_scale_max_freq_capacity(struct sched_domain *sd, int cpu)
+{
+ return per_cpu(max_freq_scale, cpu);
+}
+
static void __cpufreq_notify_transition(struct cpufreq_policy *policy,
struct cpufreq_freqs *freqs, unsigned int state)
{
@@ -2253,6 +2285,8 @@
blocking_notifier_call_chain(&cpufreq_policy_notifier_list,
CPUFREQ_NOTIFY, new_policy);
+ scale_max_freq_capacity(policy->cpus, policy->max);
+
policy->min = new_policy->min;
policy->max = new_policy->max;
trace_cpu_frequency_limits(policy->max, policy->min, policy->cpu);
diff --git a/include/linux/cpufreq.h b/include/linux/cpufreq.h
index 8fe5e55..4525eee 100644
--- a/include/linux/cpufreq.h
+++ b/include/linux/cpufreq.h
@@ -941,4 +941,5 @@
struct sched_domain;
unsigned long cpufreq_scale_freq_capacity(struct sched_domain *sd, int cpu);
+unsigned long cpufreq_scale_max_freq_capacity(struct sched_domain *sd, int cpu);
#endif /* _LINUX_CPUFREQ_H */