SCHEDULING OF STOCHASTIC TASKS ON 2 PARALLEL PROCESSORS

The paper considers the problem of scheduling n tasks on two identical parallel processors. It shows both in the case when the processing times for the n tasks are independent exponential random variables, and when they are independent hyperexponentials which are mixtures of two fixed exponentials, that the policy of performing tasks with longest expected processing time (LEPT) first minimizes the expected makespan, and that in the hyperexponential case the policy of performing tasks with shortest expected processing time (SEPT) first minimizes the expected flow time. The approach is simpler than the dynamic programming approach recently employed by J. Bruno and P. Downey.