ANDROID: arm: Cpu invariant scheduler load-tracking and capacity support
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 instead of the arm arch specific cpu_efficiency and
dtb property 'clock-frequency' values 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>
Signed-off-by: Andres Oportus <andresoportus@google.com>
diff --git a/arch/arm/kernel/topology.c b/arch/arm/kernel/topology.c
index 489e63a..b2cefdf 100644
--- a/arch/arm/kernel/topology.c
+++ b/arch/arm/kernel/topology.c
@@ -153,6 +153,8 @@ static void __init parse_dt_topology(void)
}
+static const struct sched_group_energy * const cpu_core_energy(int cpu);
+
/*
* Look for a customed capacity of a CPU in the cpu_capacity table during the
* boot. The update of all CPUs is in O(n^2) for heteregeneous system but the
@@ -160,10 +162,14 @@ static void __init parse_dt_topology(void)
*/
static void update_cpu_capacity(unsigned int cpu)
{
- if (!cpu_capacity(cpu))
- return;
+ unsigned long capacity = SCHED_CAPACITY_SCALE;
- set_capacity_scale(cpu, cpu_capacity(cpu) / middle_capacity);
+ 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%u: update cpu_capacity %lu\n",
cpu, arch_scale_cpu_capacity(NULL, cpu));