[PATCH v6 4/6] sched: get CPU's usage statistic

Vincent Guittot
2014-09-23T16:10:47Z

Monitor the usage level of each group of each sched_domain level. The usage is
the amount of cpu_capacity that is currently used on a CPU or group of CPUs.
We use the utilization_load_avg to evaluate the usage level of each group.

Signed-off-by: Vincent Guittot <vincent.guittot@linaro.org>
---
kernel/sched/fair.c | 13 +++++++++++++
1 file changed, 13 insertions(+)

diff --git a/kernel/sched/fair.c b/kernel/sched/fair.c
index 2cf153d..4097e3f 100644
--- a/kernel/sched/fair.c
+++ b/kernel/sched/fair.c
@@ -4523,6 +4523,17 @@ static int select_idle_sibling(struct task_struct *p, int target)
return target;
}

+static int get_cpu_usage(int cpu)
+{
+ unsigned long usage = cpu_rq(cpu)->cfs.utilization_load_avg;
+ unsigned long capacity = capacity_orig_of(cpu);
+
+ if (usage >= SCHED_LOAD_SCALE)
+ return capacity + 1;
+
+ return (usage * capacity) >> SCHED_LOAD_SHIFT;
+}
+
/*
* select_task_rq_fair: Select target runqueue for the waking task in domains
* that have the 'sd_flag' flag set. In practice, this is SD_BALANCE_WAKE,
@@ -5663,6 +5674,7 @@ struct sg_lb_stats {
unsigned long sum_weighted_load; /* Weighted load of group's tasks */
unsigned long load_per_task;
unsigned long group_capacity;
+ unsigned long group_usage; /* Total usage of the group */
unsigned int sum_nr_running; /* Nr tasks running in the group */
unsigned int group_capacity_factor;
unsigned int idle_cpus;
@@ -6037,6 +6049,7 @@ static inline void update_sg_lb_stats(struct lb_env *env,
load = source_load(i, load_idx);

sgs->group_load += load;
+ sgs->group_usage += get_cpu_usage(i);
sgs->sum_nr_running += rq->cfs.h_nr_running;

if (rq->nr_running > 1)
--
1.9.1