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| author | Dietmar Eggemann <dietmar.eggemann@arm.com> | 2015-09-25 17:34:15 +0100 |
|---|---|---|
| committer | Punit Agrawal <punit.agrawal@arm.com> | 2016-03-21 12:34:30 +0000 |
| commit | 51f57a62888f44ef9694660edf408e05dcf7f31e (patch) | |
| tree | 583ccb7bd7fcbca54c7f327c277b39d4c7d41b8d | |
| parent | 5f21ffcba8f88b503b39040d7c3f45bdb3167ddc (diff) | |
arm64: 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.
Including <linux/cpufreq.h> in topology.h like for the arm arch doesn't
work because of CONFIG_COMPAT=y (Kernel support for 32-bit EL0).
That's why cpufreq_scale_max_freq_capacity() has to be declared extern
in topology.h.
Signed-off-by: Dietmar Eggemann <dietmar.eggemann@arm.com>
| -rw-r--r-- | arch/arm64/include/asm/topology.h | 1 | ||||
| -rw-r--r-- | arch/arm64/kernel/topology.c | 6 |
2 files changed, 7 insertions, 0 deletions
diff --git a/arch/arm64/include/asm/topology.h b/arch/arm64/include/asm/topology.h index 9370a336c934..bbd362cd1ed1 100644 --- a/arch/arm64/include/asm/topology.h +++ b/arch/arm64/include/asm/topology.h @@ -26,6 +26,7 @@ struct sched_domain; #ifdef CONFIG_CPU_FREQ #define arch_scale_freq_capacity cpufreq_scale_freq_capacity extern unsigned long cpufreq_scale_freq_capacity(struct sched_domain *sd, int cpu); +extern unsigned long cpufreq_scale_max_freq_capacity(int cpu); #endif #define arch_scale_cpu_capacity scale_cpu_capacity extern unsigned long scale_cpu_capacity(struct sched_domain *sd, int cpu); diff --git a/arch/arm64/kernel/topology.c b/arch/arm64/kernel/topology.c index b5b43af6a7dc..5b2c67a510d8 100644 --- a/arch/arm64/kernel/topology.c +++ b/arch/arm64/kernel/topology.c @@ -29,7 +29,13 @@ static DEFINE_PER_CPU(unsigned long, cpu_scale) = SCHED_CAPACITY_SCALE; unsigned long scale_cpu_capacity(struct sched_domain *sd, int cpu) { +#ifdef 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) |