1. A method of scheduling threads in a multiprocessor computer, the method comprising: selecting a thread in a ready queue to be dispatched to a processor; determining whether an interrupt mask flag is set in a thread control block associated with the thread, if the interrupt mask flag is set in the thread control block associated with the thread, selecting a processor; setting a current processor priority register of the selected processor to least favored; and dispatching the thread from the ready queue to the selected processor.