A simple proof technique for priority-scheduled systems

Abstract

A simple proof method is presented for proving invariance properties of concurrent programs in priority-scheduled systems. This method is illustrated by using it to establish the correctness of a simple wait-free consensus algorithm for priority-scheduled uniprocessor systems. This consensus algorithm is of interest in its own right because is shows that atomic read and write operations are universal in priority-scheduled uniprocessor systems, i.e., they can be used to implement any shared object in such a system in a wait-free manner. This stands in contrast to fully asynchronous systems, where strong synchronization primitives such as compare-and-swap are needed for universality.