Open Questions

Are priorities necessary for good performance within an application in addition to between applications?
What is a reasonable policy concerning starvation?
What is the performance cost of having arbitrary priority levels?

Ideas for preventing starvation

Require that the number of CPU-bound high priority threads is lower than the number of cores.
Ensure there is at least one core to run only low priority threads, even if that means putting more than one high-priority thread on the same core.