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| author | Dietmar Eggemann <dietmar.eggemann@arm.com> | 2017-09-26 17:41:10 +0100 |
|---|---|---|
| committer | Rafael J. Wysocki <rafael.j.wysocki@intel.com> | 2017-10-03 02:37:53 +0200 |
| commit | 0e27c567d1673137b06aa96bb7aef635fb657dee (patch) | |
| tree | bcbb7041ef1af0a73336595a4e9d72ec5fedb813 | |
| parent | 400ec74d3b3784a48b09db9518aa2c4b6d4e497f (diff) | |
| download | linux-0e27c567d1673137b06aa96bb7aef635fb657dee.tar.bz2 | |
drivers base/arch_topology: provide frequency-invariant accounting support
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.
Signed-off-by: Dietmar Eggemann <dietmar.eggemann@arm.com>
Acked-by: Viresh Kumar <viresh.kumar@linaro.org>
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
| -rw-r--r-- | drivers/base/arch_topology.c | 14 | ||||
| -rw-r--r-- | include/linux/arch_topology.h | 9 |
2 files changed, 23 insertions, 0 deletions
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_ */ |