sched: Load-balancing within HMP domain in the HMP scheduler

Hi.

I have been trying to apply Linaro's HMP scheduler to a big.LITTLE machine, which has 4 big and 4 LITTLE cores. However, I could only utilize two cores with the HMP scheduler.

While hmp_select_faster_cpu() always selects the first core in the big cluster and hmp_select_slower_cpu() always selects the first core in the LITTLE cluster, I found that my kernel with the HMP scheduler does no load-balancing at all within each HMP domain(big/LITTLE cluster).

The function rebalance_domains() does almost nothing, because SD_LOAD_BALANCE flags for the sched_domains are always false. It's the same in select_task_rq_fair().

I'm wondering if this is normal, although I believe it shouldn't be. If it's not, how can I get the HMP scheduler to perform load-balancing within an HMP domain? What might I be doing wrong here?

Thanks.

- Antonio