[Patch v9 4/8] sched/fair: Enable periodic update of average thermal pressure

From: Thara Gopinath
Date: Tue Jan 28 2020 - 17:36:26 EST


Introduce support in scheduler periodic tick and other CFS bookkeeping
apis to trigger the process of computing average thermal pressure for a
cpu. Also consider avg_thermal.load_avg in others_have_blocked which
allows for decay of pelt signals.

Signed-off-by: Thara Gopinath <thara.gopinath@xxxxxxxxxx>
---

v8->v9:
- Moved periodic triggering of thermal pressure averaging from CFS
tick function to generic scheduler core tick function.

kernel/sched/core.c | 3 +++
kernel/sched/fair.c | 5 +++++
2 files changed, 8 insertions(+)

diff --git a/kernel/sched/core.c b/kernel/sched/core.c
index fc1dfc0..b921795 100644
--- a/kernel/sched/core.c
+++ b/kernel/sched/core.c
@@ -3594,12 +3594,15 @@ void scheduler_tick(void)
struct rq *rq = cpu_rq(cpu);
struct task_struct *curr = rq->curr;
struct rq_flags rf;
+ unsigned long thermal_pressure;

sched_clock_tick();

rq_lock(rq, &rf);

update_rq_clock(rq);
+ thermal_pressure = arch_cpu_thermal_pressure(cpu_of(rq));
+ update_thermal_load_avg(rq_clock_task(rq), rq, thermal_pressure);
curr->sched_class->task_tick(rq, curr, 0);
calc_global_load_tick(rq);
psi_task_tick(rq);
diff --git a/kernel/sched/fair.c b/kernel/sched/fair.c
index ebf5095..5f58c03 100644
--- a/kernel/sched/fair.c
+++ b/kernel/sched/fair.c
@@ -7491,6 +7491,9 @@ static inline bool others_have_blocked(struct rq *rq)
if (READ_ONCE(rq->avg_dl.util_avg))
return true;

+ if (thermal_load_avg(rq))
+ return true;
+
#ifdef CONFIG_HAVE_SCHED_AVG_IRQ
if (READ_ONCE(rq->avg_irq.util_avg))
return true;
@@ -7516,6 +7519,7 @@ static bool __update_blocked_others(struct rq *rq, bool *done)
{
const struct sched_class *curr_class;
u64 now = rq_clock_pelt(rq);
+ unsigned long thermal_pressure = arch_cpu_thermal_pressure(cpu_of(rq));
bool decayed;

/*
@@ -7526,6 +7530,7 @@ static bool __update_blocked_others(struct rq *rq, bool *done)

decayed = update_rt_rq_load_avg(now, rq, curr_class == &rt_sched_class) |
update_dl_rq_load_avg(now, rq, curr_class == &dl_sched_class) |
+ update_thermal_load_avg(rq_clock_task(rq), rq, thermal_pressure) |
update_irq_load_avg(rq, 0);

if (others_have_blocked(rq))
--
2.1.4