[RFCv5 PATCH 19/46] sched: Compute cpu capacity available at current frequency

Morten Rasmussen
2015-07-07T19:01:08Z

capacity_orig_of() returns the max available compute capacity of a cpu.
For scale-invariant utilization tracking and energy-aware scheduling
decisions it is useful to know the compute capacity available at the
current OPP of a cpu.

cc: Ingo Molnar <mingo@redhat.com>
cc: Peter Zijlstra <peterz@infradead.org>

Signed-off-by: Morten Rasmussen <morten.rasmussen@arm.com>
---
kernel/sched/fair.c | 11 +++++++++++
1 file changed, 11 insertions(+)

diff --git a/kernel/sched/fair.c b/kernel/sched/fair.c
index a95dad9..70f81fc 100644
--- a/kernel/sched/fair.c
+++ b/kernel/sched/fair.c
@@ -4791,6 +4791,17 @@ static long effective_load(struct task_group *tg, int cpu, long wl, long wg)

#endif

+/*
+ * Returns the current capacity of cpu after applying both
+ * cpu and freq scaling.
+ */
+static unsigned long capacity_curr_of(int cpu)
+{
+ return cpu_rq(cpu)->cpu_capacity_orig *
+ arch_scale_freq_capacity(NULL, cpu)
+ >> SCHED_CAPACITY_SHIFT;
+}
+
static inline bool energy_aware(void)
{
return sched_feat(ENERGY_AWARE);
--
1.9.1