Deadlock detection without wait-for graphs

Deadlock detection is an important service that the run-time system of a parallel environment should provide. In parallel programs deadlock can occur when the different processes are waiting for various events, as opposed to concurrent systems, where deadlock occurs when processes wait for resources held by other processes. Therefore classical deadlock detection techniques such as checking for cycles in the wait-for graph are unapplicable. An alternative algorithm that checks whether all the processes are blocked is presented. This algorithm deals with situations in which the state transition from blocked to unblocked is indirect, as may happen when busy-waiting is used.