A Non-Preemptive Two-Class M/M/1 System with Prioritized Real-Time Jobs under Earliest-Deadline-First Policy

This paper introduces an analytical method for approximating the performance of a two-classpriority m/m/1 system. the system is fully non-preemptive. more specifically, the prioritizedclass-1 jobs are real-time and served with the non-preemptive earliest-deadline-first (edf)policy, but despite their priority cannot preempt any non real-time class-2 job. the waitingclass-2 jobs can only be served from the time instant that no class-1 job is in the system. theservice discipline of the class-2 jobs is fcfs. the required mean service times may depend onthe class of the jobs. the real-time jobs have exponentially distributed relative deadlines untilthe end of service. the system is approximated by a markovian model in the long run, whichcan be solved numerically using standard markovian solution techniques. the performancemeasures of the system are the loss probability of the class-1 jobs and the mean sojourn(waiting) time of the class-2 jobs. comparing the numerical and simulation results, we find thatthe existing errors are relatively small.