Optimal priority assignment in the presence of blocking

The optimality of Deadline Monotonic Priority Ordering (DMPO) for synchronous systems under Priority Ceiling Protocol (PCP) in the presence of blocking is discussed. A priority assignment algorithm which is optimal to asynchronous systems when shared resources additionally exist, is introduced. Feasible priority orderings are identified by traversal of the permutation tree for the set of process in consideration. The optimality of DMPO for synchronous systems with shared resources accessed under the PCP is proved, and the priority assignment algorithm is shown to be applicable to systems with self-suspending process.