On 02/15/12 21:54, Jeff Roberson wrote:

I haven't got good idea yet about balancing priorities, but I've rewritten balancer itself. As soon as sched_lowest() / sched_highest() are more intelligent now, they allowed to remove topology traversing from the balancer itself. That should fix double-swapping problem, allow to keep some affinity while moving threads and make balancing more fair. I did number of tests running 4, 8, 9 and 16 CPU-bound threads on 8 CPUs. With 4, 8 and 16 threads everything is stationary as it should. With 9 threads I see regular and random load move between all 8 CPUs. Measurements on 5 minutes run show deviation of only about 5 seconds. It is the same deviation as I see caused by only scheduling of 16 threads on 8 cores without any balancing needed at all. So I believe this code works as it should.

Here is the patch: http://people.freebsd.org/~mav/sched.htt40.patch

I plan this to be a final patch of this series (more to come :)) and if there will be no problems or objections, I am going to commit it (except some debugging KTRs) in about ten days. So now it's a good time for reviews and testing. :)