Subject: sched: Add IRQ utilization tracking
From: Peter Zijlstra <peterz@infradead.org>
Date: Mon Aug 7 17:22:46 CEST 2017

Track how much time we spend on IRQ...

Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
---
 kernel/sched/core.c  |    6 +++++-
 kernel/sched/fair.c  |   12 ++++++++++++
 kernel/sched/sched.h |    2 ++
 3 files changed, 19 insertions(+), 1 deletion(-)

--- a/kernel/sched/core.c
+++ b/kernel/sched/core.c
@@ -151,6 +151,8 @@ struct rq *task_rq_lock(struct task_stru
 	}
 }
 
+extern int update_irq_load_avg(u64 now, int cpu, struct rq *rq, int running);
+
 /*
  * RQ-clock updating methods:
  */
@@ -204,8 +206,10 @@ static void update_rq_clock_task(struct
 	rq->clock_task += delta;
 
 #if defined(CONFIG_IRQ_TIME_ACCOUNTING) || defined(CONFIG_PARAVIRT_TIME_ACCOUNTING)
-	if ((irq_delta + steal) && sched_feat(NONTASK_CAPACITY))
+	if ((irq_delta + steal) && sched_feat(NONTASK_CAPACITY)) {
 		sched_rt_avg_update(rq, irq_delta + steal);
+		update_irq_load_avg(rq->clock, cpu_of(rq), rq, 1);
+	}
 #endif
 }
 
--- a/kernel/sched/fair.c
+++ b/kernel/sched/fair.c
@@ -3012,6 +3012,11 @@ __update_load_avg_cfs_rq(u64 now, int cp
 			cfs_rq->curr != NULL, cfs_rq);
 }
 
+int update_irq_load_avg(u64 now, int cpu, struct rq *rq, int running)
+{
+	return ___update_load_avg(now, cpu, &rq->irq_avg, 0, running, NULL);
+}
+
 int update_rt_rq_load_avg(u64 now, int cpu, struct rt_rq *rt_rq, int running)
 {
 	return ___update_load_avg(now, cpu, &rt_rq->avg, 0, running, NULL);
@@ -3550,6 +3555,11 @@ update_cfs_rq_load_avg(u64 now, struct c
 	return 0;
 }
 
+int update_irq_load_avg(u64 now, int cpu, struct rq *rq, int running)
+{
+	return 0;
+}
+
 int update_rt_rq_load_avg(u64 now, int cpu, struct rt_rq *rt_rq, int running)
 {
 	return 0;
@@ -6926,6 +6936,7 @@ static void update_blocked_averages(int
 
 	rq_lock_irqsave(rq, &rf);
 	update_rq_clock(rq);
+	update_irq_load_avg(rq_clock(rq), cpu, rq, 0);
 
 	/*
 	 * Iterates the task_group tree in a bottom up fashion, see
@@ -7014,6 +7025,7 @@ static inline void update_blocked_averag
 
 	rq_lock_irqsave(rq, &rf);
 	update_rq_clock(rq);
+	update_irq_load_avg(rq_clock(rq), cpu, rq, 0);
 	update_cfs_rq_load_avg(cfs_rq_clock_task(cfs_rq), cfs_rq, true);
 	update_rt_rq_load_avg(rq_clock_task(rq), cpu, &rq->rt, 0);
 	update_dl_rq_load_avg(rq_clock_task(rq), cpu, &rq->dl, 0);
--- a/kernel/sched/sched.h
+++ b/kernel/sched/sched.h
@@ -748,6 +748,8 @@ struct rq {
 
 	struct list_head cfs_tasks;
 
+	struct sched_avg irq_avg;
+
 	u64 rt_avg;
 	u64 age_stamp;
 	u64 idle_stamp;