[Patch v6 5/7] sched/fair: update cpu_capacity to reflect thermal pressure

From: Thara Gopinath
Date: Wed Dec 11 2019 - 23:12:04 EST


cpu_capacity relflects the maximum available capacity of a cpu. Thermal
pressure on a cpu means this maximum available capacity is reduced. This
patch reduces the average thermal pressure for a cpu from its maximum
available capacity so that cpu_capacity reflects the actual
available capacity.

Signed-off-by: Thara Gopinath <thara.gopinath@xxxxxxxxxx>
---
kernel/sched/fair.c | 7 +++++++
1 file changed, 7 insertions(+)

diff --git a/kernel/sched/fair.c b/kernel/sched/fair.c
index e12a375..4840655 100644
--- a/kernel/sched/fair.c
+++ b/kernel/sched/fair.c
@@ -7725,8 +7725,15 @@ static unsigned long scale_rt_capacity(struct sched_domain *sd, int cpu)
if (unlikely(irq >= max))
return 1;

+ /*
+ * avg_rt.util avg and avg_dl.util track binary signals
+ * (running and not running) with weights 0 and 1024 respectively.
+ * avg_thermal.load_avg tracks thermal pressure and the weighted
+ * average uses the actual delta max capacity.
+ */
used = READ_ONCE(rq->avg_rt.util_avg);
used += READ_ONCE(rq->avg_dl.util_avg);
+ used += READ_ONCE(rq->avg_thermal.load_avg);

if (unlikely(used >= max))
return 1;
--
2.1.4