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| author | Dietmar Eggemann <dietmar.eggemann@arm.com> | 2015-09-23 17:59:55 +0100 |
|---|---|---|
| committer | Punit Agrawal <punit.agrawal@arm.com> | 2016-03-21 12:34:30 +0000 |
| commit | 5f21ffcba8f88b503b39040d7c3f45bdb3167ddc (patch) | |
| tree | 0f5ec0743978d6bada4133670ab6f44ecf39fc18 | |
| parent | 500f94bc1cfeb6846314fa151c81d01607c259a7 (diff) | |
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 <dietmar.eggemann@arm.com>
| -rw-r--r-- | arch/arm/kernel/topology.c | 6 |
1 files changed, 6 insertions, 0 deletions
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) |