If there have runnable tasks number is bigger than CPU number in one schedule group, then this sched_group load_avg signal will be under estimated due the CPU load_avg value cannot accumulate all running tasks load value.
On the other hand, if another sched_group CPU has less tasks number than CPU number. As the result, the first sched_group's per_task_load will be much less than second CPU's value.
So this patch is to consider this situation and set imbalance as to busiest->load_per_task.
Signed-off-by: Leo Yan leo.yan@linaro.org --- kernel/sched/fair.c | 6 ++++++ 1 file changed, 6 insertions(+)
diff --git a/kernel/sched/fair.c b/kernel/sched/fair.c index 06b0e1b..ab99b6f 100644 --- a/kernel/sched/fair.c +++ b/kernel/sched/fair.c @@ -7604,6 +7604,12 @@ void fix_small_imbalance(struct lb_env *env, struct sd_lb_stats *sds) local = &sds->local_stat; busiest = &sds->busiest_stat;
+ if (busiest->sum_nr_running >= busiest->group_weight && + local->sum_nr_running < local->group_weight) { + env->imbalance = busiest->load_per_task; + return; + } + if (!local->sum_nr_running) local->load_per_task = cpu_avg_load_per_task(env->dst_cpu); else if (busiest->load_per_task > local->load_per_task) -- 1.9.1