[Patch v5 3/6] sched/fair: Enable periodic update of average thermal pressure

From: Thara Gopinath
Date: Tue Nov 05 2019 - 13:50:07 EST


Introduce support in CFS periodic tick and other 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>
---

v4->v5:
- Updated both versions of update_blocked_averages to trigger the
process of computing average thermal pressure.
- Updated others_have_blocked to considerd avg_thermal.load_avg.

kernel/sched/fair.c | 10 ++++++++++
1 file changed, 10 insertions(+)

diff --git a/kernel/sched/fair.c b/kernel/sched/fair.c
index 2e907cc..9fb0494 100644
--- a/kernel/sched/fair.c
+++ b/kernel/sched/fair.c
@@ -92,6 +92,8 @@ const_debug unsigned int sysctl_sched_migration_cost = 500000UL;
*/
static DEFINE_PER_CPU(unsigned long, thermal_pressure);

+static void trigger_thermal_pressure_average(struct rq *rq);
+
#ifdef CONFIG_SMP
/*
* For asym packing, by default the lower numbered CPU has higher priority.
@@ -7493,6 +7495,9 @@ static inline bool others_have_blocked(struct rq *rq)
if (READ_ONCE(rq->avg_dl.util_avg))
return true;

+ if (READ_ONCE(rq->avg_thermal.load_avg))
+ return true;
+
#ifdef CONFIG_HAVE_SCHED_AVG_IRQ
if (READ_ONCE(rq->avg_irq.util_avg))
return true;
@@ -7580,6 +7585,8 @@ static void update_blocked_averages(int cpu)
done = false;

update_blocked_load_status(rq, !done);
+
+ trigger_thermal_pressure_average(rq);
rq_unlock_irqrestore(rq, &rf);
}

@@ -7646,6 +7653,7 @@ static inline void update_blocked_averages(int cpu)
update_dl_rq_load_avg(rq_clock_pelt(rq), rq, curr_class == &dl_sched_class);
update_irq_load_avg(rq, 0);
update_blocked_load_status(rq, cfs_rq_has_blocked(cfs_rq) || others_have_blocked(rq));
+ trigger_thermal_pressure_average(rq);
rq_unlock_irqrestore(rq, &rf);
}

@@ -9939,6 +9947,8 @@ static void task_tick_fair(struct rq *rq, struct task_struct *curr, int queued)

update_misfit_status(curr, rq);
update_overutilized_status(task_rq(curr));
+
+ trigger_thermal_pressure_average(rq);
}

/*
--
2.1.4