| Message ID | 20170727193312.9849-6-dietmar.eggemann@arm.com (mailing list archive) |
|---|---|
| State | Deferred |
| Headers | show |
On 27-07-17, 20:33, Dietmar Eggemann wrote: > 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 <gregkh@linuxfoundation.org> > Cc: Juri Lelli <juri.lelli@arm.com> > Signed-off-by: Dietmar Eggemann <dietmar.eggemann@arm.com> > --- > drivers/base/arch_topology.c | 14 ++++++++++++++ > include/linux/arch_topology.h | 10 ++++++++++ > 2 files changed, 24 insertions(+) > > diff --git a/drivers/base/arch_topology.c b/drivers/base/arch_topology.c > index 562e0c93ae52..af9ab98a233e 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 9af3c174c03a..3e3c2657c9a1 100644 > --- a/include/linux/arch_topology.h > +++ b/include/linux/arch_topology.h > @@ -4,6 +4,8 @@ > #ifndef _LINUX_ARCH_TOPOLOGY_H_ > #define _LINUX_ARCH_TOPOLOGY_H_ > > +#include <linux/percpu.h> > + > void topology_normalize_cpu_scale(void); > > struct device_node; > @@ -14,4 +16,12 @@ 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_ */ Acked-by: Viresh Kumar <viresh.kumar@linaro.org>
diff --git a/drivers/base/arch_topology.c b/drivers/base/arch_topology.c index 562e0c93ae52..af9ab98a233e 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 9af3c174c03a..3e3c2657c9a1 100644 --- a/include/linux/arch_topology.h +++ b/include/linux/arch_topology.h @@ -4,6 +4,8 @@ #ifndef _LINUX_ARCH_TOPOLOGY_H_ #define _LINUX_ARCH_TOPOLOGY_H_ +#include <linux/percpu.h> + void topology_normalize_cpu_scale(void); struct device_node; @@ -14,4 +16,12 @@ 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_ */
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 <gregkh@linuxfoundation.org> Cc: Juri Lelli <juri.lelli@arm.com> Signed-off-by: Dietmar Eggemann <dietmar.eggemann@arm.com> --- drivers/base/arch_topology.c | 14 ++++++++++++++ include/linux/arch_topology.h | 10 ++++++++++ 2 files changed, 24 insertions(+)