From b03f1ba3d5bb9db0ca495c8c33ef88588daaae50 Mon Sep 17 00:00:00 2001 From: Dietmar Eggemann Date: Tue, 22 Sep 2015 16:47:48 +0100 Subject: 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 --- include/linux/cpufreq.h | 1 + 1 file changed, 1 insertion(+) (limited to 'include/linux') 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 */ -- cgit v1.2.3