From 5414a72fc30f2069e3943ceb4e39b0ba9cd9c7e3 Mon Sep 17 00:00:00 2001 From: Dietmar Eggemann Date: Wed, 23 Sep 2015 17:59:55 +0100 Subject: [PATCH] arm: Enable max freq invariant scheduler load-tracking and capacity support Maximum Frequency Invariance has to be part of Cpu Invariance because Frequency Invariance deals only with differences in load-tracking introduces by Dynamic Frequency Scaling and not with limiting the possible range of cpu frequency. By placing Maximum Frequency Invariance into Cpu Invariance, load-tracking is scaled via arch_scale_cpu_capacity() in __update_load_avg() and cpu capacity is scaled via arch_scale_cpu_capacity() in update_cpu_capacity(). To be able to save the extra multiplication in the scheduler hotpath (__update_load_avg()) we could: 1 Inform cpufreq about base cpu capacity at boot and let it handle scale_cpu_capacity() as well. 2 Use the cpufreq policy callback which would update a per-cpu current cpu_scale and this value would be return in scale_cpu_capacity(). 3 Use per-cpu current max_freq_scale and current cpu_scale with the current patch. Signed-off-by: Dietmar Eggemann --- arch/arm/kernel/topology.c | 6 ++++++ 1 file changed, 6 insertions(+) diff --git a/arch/arm/kernel/topology.c b/arch/arm/kernel/topology.c index da1c611a3b5e..0308342def8c 100644 --- a/arch/arm/kernel/topology.c +++ b/arch/arm/kernel/topology.c @@ -44,7 +44,13 @@ static DEFINE_PER_CPU(unsigned long, cpu_scale); unsigned long scale_cpu_capacity(struct sched_domain *sd, int cpu) { +#if CONFIG_CPU_FREQ + unsigned long max_freq_scale = cpufreq_scale_max_freq_capacity(cpu); + + return per_cpu(cpu_scale, cpu) * max_freq_scale >> SCHED_CAPACITY_SHIFT; +#else return per_cpu(cpu_scale, cpu); +#endif } static void set_capacity_scale(unsigned int cpu, unsigned long capacity) -- 2.20.1