2020-02-22 00:52:58

by Thara Gopinath

Subject: [Patch v10 7/9] sched/fair: update cpu_capacity to reflect thermal pressure

cpu_capacity initially reflects the maximum possible capacity of a cpu.
Thermal pressure on a cpu means this maximum possible capacity is
unavailable due to thermal events. This patch subtracts the average
thermal pressure for a cpu from its maximum possible capacity so that
cpu_capacity reflects the remaining maximum capacity.

Signed-off-by: Thara Gopinath <[email protected]>
---
v8->v9:
- Use thermal_load_avg to read rq->avg_thermal.load_avg.

kernel/sched/fair.c | 7 +++++++
1 file changed, 7 insertions(+)

diff --git a/kernel/sched/fair.c b/kernel/sched/fair.c
index 00b21a5b71f0..10e867e540ab 100644
--- a/kernel/sched/fair.c
+++ b/kernel/sched/fair.c
@@ -7800,8 +7800,15 @@ 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_avg 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(load).
+ */
used = READ_ONCE(rq->avg_rt.util_avg);
used += READ_ONCE(rq->avg_dl.util_avg);
+ used += thermal_load_avg(rq);

if (unlikely(used >= max))
return 1;
--
2.20.1

2020-03-06 14:43:51

by tip-bot2 for Alexey Makhalov

Subject: [tip: sched/core] sched/fair: Update cpu_capacity to reflect thermal pressure

The following commit has been merged into the sched/core branch of tip:

Commit-ID: 467b7d01c469dc6aa492c17d1f1d1952632728f1
Gitweb: https://git.kernel.org/tip/467b7d01c469dc6aa492c17d1f1d1952632728f1
Author: Thara Gopinath <[email protected]>
AuthorDate: Fri, 21 Feb 2020 19:52:11 -05:00
Committer: Ingo Molnar <[email protected]>
CommitterDate: Fri, 06 Mar 2020 12:57:20 +01:00

sched/fair: Update cpu_capacity to reflect thermal pressure

cpu_capacity initially reflects the maximum possible capacity of a CPU.
Thermal pressure on a CPU means this maximum possible capacity is
unavailable due to thermal events. This patch subtracts the average
thermal pressure for a CPU from its maximum possible capacity so that
cpu_capacity reflects the remaining maximum capacity.

Signed-off-by: Thara Gopinath <[email protected]>
Signed-off-by: Peter Zijlstra (Intel) <[email protected]>
Signed-off-by: Ingo Molnar <[email protected]>
Link: https://lkml.kernel.org/r/[email protected]
---
kernel/sched/fair.c | 7 +++++++
1 file changed, 7 insertions(+)

diff --git a/kernel/sched/fair.c b/kernel/sched/fair.c
index 11f8488..aa51286 100644
--- a/kernel/sched/fair.c
+++ b/kernel/sched/fair.c
@@ -7984,8 +7984,15 @@ 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_avg 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(load).
+ */
used = READ_ONCE(rq->avg_rt.util_avg);
used += READ_ONCE(rq->avg_dl.util_avg);
+ used += thermal_load_avg(rq);

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