[PATCH v4 6/6] sched: consider runnable load average in effective_load

Alex Shi
2013-04-27T05:27:31Z

effective_load calculates the load change as seen from the
root_task_group. It needs to engage the runnable average
of changed task.

Thanks for Morten Rasmussen's reminder of this.

Signed-off-by: Alex Shi <alex.shi@intel.com>
---
kernel/sched/fair.c | 27 ++++++++++++++++++++-------
1 file changed, 20 insertions(+), 7 deletions(-)

diff --git a/kernel/sched/fair.c b/kernel/sched/fair.c
index 995dfc7..27c7ebb 100644
--- a/kernel/sched/fair.c
+++ b/kernel/sched/fair.c
@@ -2998,7 +2998,8 @@ static void task_waking_fair(struct task_struct *p)

#ifdef CONFIG_FAIR_GROUP_SCHED
/*
- * effective_load() calculates the load change as seen from the root_task_group
+ * effective_load() calculates the runnable load average change as seen from
+ * the root_task_group
*
* Adding load to a group doesn't make a group heavier, but can cause movement
* of group shares between cpus. Assuming the shares were perfectly aligned one
@@ -3046,6 +3047,9 @@ static void task_waking_fair(struct task_struct *p)
* Therefore the effective change in loads on CPU 0 would be 5/56 (3/8 - 2/7)
* times the weight of the group. The effect on CPU 1 would be -4/56 (4/8 -
* 4/7) times the weight of the group.
+ *
+ * After get effective_load of the load moving, will engaged the sched entity's
+ * runnable avg.
*/
static long effective_load(struct task_group *tg, int cpu, long wl, long wg)
{
@@ -3120,6 +3124,7 @@ static int wake_affine(struct sched_domain *sd, struct task_struct *p, int sync)
struct task_group *tg;
unsigned long weight;
int balanced;
+ int runnable_avg;

idx = sd->wake_idx;
this_cpu = smp_processor_id();
@@ -3135,13 +3140,19 @@ static int wake_affine(struct sched_domain *sd, struct task_struct *p, int sync)
if (sync) {
tg = task_group(current);
weight = current->se.load.weight;
+ runnable_avg = current->se.avg.runnable_avg_sum * NICE_0_LOAD
+ / (current->se.avg.runnable_avg_period + 1);

- this_load += effective_load(tg, this_cpu, -weight, -weight);
- load += effective_load(tg, prev_cpu, 0, -weight);
+ this_load += effective_load(tg, this_cpu, -weight, -weight)
+ * runnable_avg >> NICE_0_SHIFT;
+ load += effective_load(tg, prev_cpu, 0, -weight)
+ * runnable_avg >> NICE_0_SHIFT;
}

tg = task_group(p);
weight = p->se.load.weight;
+ runnable_avg = p->se.avg.runnable_avg_sum * NICE_0_LOAD
+ / (p->se.avg.runnable_avg_period + 1);

/*
* In low-load situations, where prev_cpu is idle and this_cpu is idle
@@ -3153,16 +3164,18 @@ static int wake_affine(struct sched_domain *sd, struct task_struct *p, int sync)
* task to be woken on this_cpu.
*/
if (this_load > 0) {
- s64 this_eff_load, prev_eff_load;
+ s64 this_eff_load, prev_eff_load, tmp_eff_load;

this_eff_load = 100;
this_eff_load *= power_of(prev_cpu);
- this_eff_load *= this_load +
- effective_load(tg, this_cpu, weight, weight);
+ tmp_eff_load = effective_load(tg, this_cpu, weight, weight)
+ * runnable_avg >> NICE_0_SHIFT;
+ this_eff_load *= this_load + tmp_eff_load;

prev_eff_load = 100 + (sd->imbalance_pct - 100) / 2;
prev_eff_load *= power_of(this_cpu);
- prev_eff_load *= load + effective_load(tg, prev_cpu, 0, weight);
+ prev_eff_load *= load + (effective_load(tg, prev_cpu, 0, weight)
+ * runnable_avg >> NICE_0_SHIFT);

balanced = this_eff_load <= prev_eff_load;
} else
--
1.7.12