machines.
- Leave the long-term load balancer running by default once per second.
- Enable stealing load from the idle thread only when the remote processor
has more than two transferable tasks. Setting this to one further
improves buildworld. Setting it higher improves mysql.
- Remove the bogus pick_zero option. I had not intended to commit this.
- Entirely disallow migration for threads with SRQ_YIELDING set. This
balances out the extra migration allowed for with the load balancers.
It also makes pick_pri perform better as I had anticipated.
Tested by: Dmitry Morozovsky <marck@rinet.ru>
Approved by: re