Problem: The current -rt, 2.6.31.4-rt14, has several load balancing issues. It can easily be seen with dbench running with the same number of processes as the number of cpus on a SMP system. The dbench threads are running as SCHED_OTHER processes. Several threads end up running on the same cpu even though other cpus are idling. This results in severe throughput regression. Peter Zijlstra posted several load balance patches meant for mainline a while ago. The following patch series is a backport of the same to 2.6.31.4-rt14. Peter's original patches can be found at http://marc.info/?l=linux-kernel&m=125198436208787&w=2 Patches 1 through 14 are backports of the original patches except patch 10 which has the original code + bug fixes. Patches 15 - 17 are various relevant fixes that have gone on top of the original patches. With these patches, load balancing improves considerably on -rt. However it does not completely resolve the problem. This is still under investigation. This has been stress tested on x86_64 and i686 -Dinakar -- -- To unsubscribe from this list: send the line "unsubscribe linux-rt-users" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
