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arm64: Cpu invariant scheduler load-tracking and capacity support

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Provides the scheduler with a cpu scaling correction factor for more
accurate load-tracking and cpu capacity handling.

The Energy Model (EM) (in fact the capacity value of the last element
of the capacity states vector of the core (MC) level sched_group_energy
structure) is used as the source for this cpu scaling factor.

The cpu capacity value depends on the micro-architecture and the
maximum frequency of the cpu.

The maximum frequency part should not be confused with the frequency
invariant scheduler load-tracking support which deals with frequency
related scaling due to DFVS functionality.

Signed-off-by: Juri Lelli <juri.lelli@arm.com>
Signed-off-by: Dietmar Eggemann <dietmar.eggemann@arm.com>
This commit is contained in:
Juri Lelli 2015-04-30 11:53:48 +01:00 • committed by Amit Pundir
parent 58342bc498
commit 70a528b9ad
2 changed files with 45 additions and 1 deletions
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4
arch/arm64/include/asm/topology.h
View file

@ -22,11 +22,13 @@ void init_cpu_topology(void);
void store_cpu_topology(unsigned int cpuid);
const struct cpumask *cpu_coregroup_mask(int cpu);
struct sched_domain;
#ifdef CONFIG_CPU_FREQ
#define arch_scale_freq_capacity cpufreq_scale_freq_capacity
struct sched_domain;
extern unsigned long cpufreq_scale_freq_capacity(struct sched_domain *sd, int cpu);
#endif
#define arch_scale_cpu_capacity scale_cpu_capacity
extern unsigned long scale_cpu_capacity(struct sched_domain *sd, int cpu);
#include <asm-generic/topology.h>

42
arch/arm64/kernel/topology.c
View file

@ -23,6 +23,18 @@
#include <asm/cputype.h>
#include <asm/topology.h>
static DEFINE_PER_CPU(unsigned long, cpu_scale) = SCHED_CAPACITY_SCALE;
unsigned long scale_cpu_capacity(struct sched_domain *sd, int cpu)
{
return per_cpu(cpu_scale, cpu);
}
static void set_capacity_scale(unsigned int cpu, unsigned long capacity)
{
per_cpu(cpu_scale, cpu) = capacity;
}
static int __init get_cpu_for_node(struct device_node *node)
{
struct device_node *cpu_node;
@ -211,6 +223,35 @@ const struct cpumask *cpu_coregroup_mask(int cpu)
return &cpu_topology[cpu].core_sibling;
}
static inline int cpu_corepower_flags(void)
{
return SD_SHARE_PKG_RESOURCES | SD_SHARE_POWERDOMAIN | \
SD_SHARE_CAP_STATES;
}
static struct sched_domain_topology_level arm64_topology[] = {
#ifdef CONFIG_SCHED_MC
{ cpu_coregroup_mask, cpu_corepower_flags, cpu_core_energy, SD_INIT_NAME(MC) },
#endif
{ cpu_cpu_mask, NULL, cpu_cluster_energy, SD_INIT_NAME(DIE) },
{ NULL, },
};
static void update_cpu_capacity(unsigned int cpu)
{
unsigned long capacity = SCHED_CAPACITY_SCALE;
if (cpu_core_energy(cpu)) {
int max_cap_idx = cpu_core_energy(cpu)->nr_cap_states - 1;
capacity = cpu_core_energy(cpu)->cap_states[max_cap_idx].cap;
}
set_capacity_scale(cpu, capacity);
pr_info("CPU%d: update cpu_capacity %lu\n",
cpu, arch_scale_cpu_capacity(NULL, cpu));
}
static void update_siblings_masks(unsigned int cpuid)
{
struct cpu_topology *cpu_topo, *cpuid_topo = &cpu_topology[cpuid];
@ -272,6 +313,7 @@ void store_cpu_topology(unsigned int cpuid)
topology_populated:
update_siblings_masks(cpuid);
update_cpu_capacity(cpuid);
}
static void __init reset_cpu_topology(void)