diff options
| author | Dietmar Eggemann <dietmar.eggemann@arm.com> | 2015-09-17 16:10:56 +0100 |
|---|---|---|
| committer | Leo Yan <leo.yan@linaro.org> | 2016-05-10 16:49:48 +0800 |
| commit | 259bd4cd8a4c5776e86ae1a86f1f8e1168e84212 (patch) | |
| tree | dbdc4dbc80be329a015e6898d052664fa07aba19 /drivers/cpufreq | |
| parent | 0ecbd590a7175818fcbccc9d5b1dc819aae25c86 (diff) | |
cpufreq: Frequency invariant scheduler load-tracking support
Implements cpufreq_scale_freq_capacity() to provide the scheduler with a
frequency scaling correction factor for more accurate load-tracking.
The factor is:
current_freq(cpu) << SCHED_CAPACITY_SHIFT / max_freq(cpu)
In fact, 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 freq_scale.
Signed-off-by: Dietmar Eggemann <dietmar.eggemann@arm.com>
Diffstat (limited to 'drivers/cpufreq')
| -rw-r--r-- | drivers/cpufreq/cpufreq.c | 29 |
1 files changed, 29 insertions, 0 deletions
diff --git a/drivers/cpufreq/cpufreq.c b/drivers/cpufreq/cpufreq.c index 8412ce5f93a7..46a7d62c8174 100644 --- a/drivers/cpufreq/cpufreq.c +++ b/drivers/cpufreq/cpufreq.c @@ -347,6 +347,31 @@ static void adjust_jiffies(unsigned long val, struct cpufreq_freqs *ci) #endif } +/********************************************************************* + * FREQUENCY INVARIANT CPU CAPACITY * + *********************************************************************/ + +static DEFINE_PER_CPU(unsigned long, 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; + int cpu; + + pr_debug("cpus %*pbl cur/cur max freq %lu/%u kHz freq scale %lu\n", + cpumask_pr_args(policy->cpus), cur, policy->max, scale); + + for_each_cpu(cpu, policy->cpus) + per_cpu(freq_scale, cpu) = scale; +} + +unsigned long cpufreq_scale_freq_capacity(struct sched_domain *sd, int cpu) +{ + return per_cpu(freq_scale, cpu); +} + static void __cpufreq_notify_transition(struct cpufreq_policy *policy, struct cpufreq_freqs *freqs, unsigned int state) { @@ -450,6 +475,8 @@ wait: spin_unlock(&policy->transition_lock); + scale_freq_capacity(policy, freqs); + cpufreq_notify_transition(policy, freqs, CPUFREQ_PRECHANGE); } EXPORT_SYMBOL_GPL(cpufreq_freq_transition_begin); @@ -2126,6 +2153,8 @@ static int cpufreq_set_policy(struct cpufreq_policy *policy, blocking_notifier_call_chain(&cpufreq_policy_notifier_list, CPUFREQ_NOTIFY, new_policy); + scale_freq_capacity(new_policy, NULL); + policy->min = new_policy->min; policy->max = new_policy->max; |