> After all, the higher priority job could always just force a cooperating
> job to yield if needed.

But it would be better for the cooperating process to be able to put
*itself* to the back of the line..  That way, the "cooperative" nature
of the process-scheduling behavior is localized in the business-logic
rather than centralized in a process-manager.  Something like;
Processor yield: true or Processor yield: false?