[RFCv6,01/10] sched: Compute cpu capacity available at current frequency

Commit Message

Steve Muckle Dec. 9, 2015, 6:19 a.m. UTC

From: Morten Rasmussen <[e-mail]>

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 <[e-mail]>
cc: Peter Zijlstra <[e-mail]>
Signed-off-by: Morten Rasmussen <[e-mail]>
Signed-off-by: Steve Muckle <[e-mail]>
---
 kernel/sched/fair.c | 11 +++++++++++
 1 file changed, 11 insertions(+)

Patch

diff --git a/kernel/sched/fair.c b/kernel/sched/fair.c
index 1093873..95b83c4 100644
--- a/kernel/sched/fair.c
+++ b/kernel/sched/fair.c
@@ -4737,6 +4737,17 @@  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;
+}
+
+/*
  * Detect M:N waker/wakee relationships via a switching-frequency heuristic.
  * A waker of many should wake a different task than the one last awakened
  * at a frequency roughly N times higher than one of its wakees.  In order