diff options
| author | Dietmar Eggemann <dietmar.eggemann@arm.com> | 2015-09-22 16:47:48 +0100 |
|---|---|---|
| committer | Punit Agrawal <punit.agrawal@arm.com> | 2016-03-21 12:34:30 +0000 |
| commit | 25fd93de74994e4bdcec2ec4ed0814207a8e0e4b (patch) | |
| tree | e4844acbf0f2d0001fa454e1382bd06b579dd3a7 | |
| parent | f903bd14ff9d8d0ef499f3fff6cb93f72932e4d9 (diff) | |
cpufreq: Max freq invariant scheduler load-tracking and cpu capacity support
Implements cpufreq_scale_max_freq_capacity() to provide the scheduler
with a maximum frequency scaling correction factor for more accurate
load-tracking and cpu capacity handling by being able to deal with
frequency capping.
This scaling factor describes the influence of running a cpu with a
current maximum frequency lower than the absolute possible maximum
frequency on load tracking and cpu capacity.
The factor is:
current_max_freq(cpu) << SCHED_CAPACITY_SHIFT / max_freq(cpu)
In fact, max_freq_scale should be a struct cpufreq_policy data member.
But this would require that the scheduler hot path (__update_load_avg())
would have to grab the cpufreq lock. This can be avoided by using per-cpu
data initialized to SCHED_CAPACITY_SCALE for max_freq_scale.
Signed-off-by: Dietmar Eggemann <dietmar.eggemann@arm.com>
| -rw-r--r-- | drivers/cpufreq/cpufreq.c | 19 | ||||
| -rw-r--r-- | include/linux/cpufreq.h | 1 |
2 files changed, 20 insertions, 0 deletions
diff --git a/drivers/cpufreq/cpufreq.c b/drivers/cpufreq/cpufreq.c index 46a7d62c8174..96f1a8860819 100644 --- a/drivers/cpufreq/cpufreq.c +++ b/drivers/cpufreq/cpufreq.c @@ -352,12 +352,14 @@ static void adjust_jiffies(unsigned long val, struct cpufreq_freqs *ci) *********************************************************************/ static DEFINE_PER_CPU(unsigned long, freq_scale) = SCHED_CAPACITY_SCALE; +static DEFINE_PER_CPU(unsigned long, max_freq_scale) = SCHED_CAPACITY_SCALE; static void scale_freq_capacity(struct cpufreq_policy *policy, struct cpufreq_freqs *freqs) { unsigned long cur = freqs ? freqs->new : policy->cur; unsigned long scale = (cur << SCHED_CAPACITY_SHIFT) / policy->max; + struct cpufreq_cpuinfo *cpuinfo = &policy->cpuinfo; int cpu; pr_debug("cpus %*pbl cur/cur max freq %lu/%u kHz freq scale %lu\n", @@ -365,6 +367,18 @@ scale_freq_capacity(struct cpufreq_policy *policy, struct cpufreq_freqs *freqs) for_each_cpu(cpu, policy->cpus) per_cpu(freq_scale, cpu) = scale; + + if (freqs) + return; + + scale = (policy->max << SCHED_CAPACITY_SHIFT) / cpuinfo->max_freq; + + pr_debug("cpus %*pbl cur max/max freq %u/%u kHz max freq scale %lu\n", + cpumask_pr_args(policy->cpus), policy->max, cpuinfo->max_freq, + scale); + + for_each_cpu(cpu, policy->cpus) + per_cpu(max_freq_scale, cpu) = scale; } unsigned long cpufreq_scale_freq_capacity(struct sched_domain *sd, int cpu) @@ -372,6 +386,11 @@ unsigned long cpufreq_scale_freq_capacity(struct sched_domain *sd, int cpu) return per_cpu(freq_scale, cpu); } +unsigned long cpufreq_scale_max_freq_capacity(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) { diff --git a/include/linux/cpufreq.h b/include/linux/cpufreq.h index 11c65f536b6c..9b1d61e1f1d7 100644 --- a/include/linux/cpufreq.h +++ b/include/linux/cpufreq.h @@ -619,4 +619,5 @@ int cpufreq_generic_init(struct cpufreq_policy *policy, struct sched_domain; unsigned long cpufreq_scale_freq_capacity(struct sched_domain *sd, int cpu); +unsigned long cpufreq_scale_max_freq_capacity(int cpu); #endif /* _LINUX_CPUFREQ_H */ |