Implements the arch-specific (arm and arm64) frequency-invariance setter function arch_set_freq_scale() which provides the following frequency scaling factor:
current_freq(cpu) << SCHED_CAPACITY_SHIFT / max_supported_freq(cpu) One possible consumer of the frequency-invariance getter function topology_get_freq_scale() is the Per-Entity Load Tracking (PELT) mechanism of the task scheduler. Allow inlining of topology_get_freq_scale() into the task scheduler fast path (e.g. __update_load_avg_se()) by coding it as a static inline function in the arch topology header file. Cc: Greg Kroah-Hartman <[email protected]> Cc: Juri Lelli <[email protected]> Signed-off-by: Dietmar Eggemann <[email protected]> Acked-by: Viresh Kumar <[email protected]> --- drivers/base/arch_topology.c | 14 ++++++++++++++ include/linux/arch_topology.h | 9 +++++++++ 2 files changed, 23 insertions(+) diff --git a/drivers/base/arch_topology.c b/drivers/base/arch_topology.c index e9bb368f32b3..416ec2f5211d 100644 --- a/drivers/base/arch_topology.c +++ b/drivers/base/arch_topology.c @@ -22,6 +22,20 @@ #include <linux/string.h> #include <linux/sched/topology.h> +DEFINE_PER_CPU(unsigned long, freq_scale) = SCHED_CAPACITY_SCALE; + +void arch_set_freq_scale(struct cpumask *cpus, unsigned long cur_freq, + unsigned long max_freq) +{ + unsigned long scale; + int i; + + scale = (cur_freq << SCHED_CAPACITY_SHIFT) / max_freq; + + for_each_cpu(i, cpus) + per_cpu(freq_scale, i) = scale; +} + static DEFINE_MUTEX(cpu_scale_mutex); static DEFINE_PER_CPU(unsigned long, cpu_scale) = SCHED_CAPACITY_SCALE; diff --git a/include/linux/arch_topology.h b/include/linux/arch_topology.h index 716ce587247e..f6e490312e4d 100644 --- a/include/linux/arch_topology.h +++ b/include/linux/arch_topology.h @@ -5,6 +5,7 @@ #define _LINUX_ARCH_TOPOLOGY_H_ #include <linux/types.h> +#include <linux/percpu.h> void topology_normalize_cpu_scale(void); @@ -16,4 +17,12 @@ unsigned long topology_get_cpu_scale(struct sched_domain *sd, int cpu); void topology_set_cpu_scale(unsigned int cpu, unsigned long capacity); +DECLARE_PER_CPU(unsigned long, freq_scale); + +static inline +unsigned long topology_get_freq_scale(struct sched_domain *sd, int cpu) +{ + return per_cpu(freq_scale, cpu); +} + #endif /* _LINUX_ARCH_TOPOLOGY_H_ */ -- 2.11.0
