Exact analysis of a priority queue with finite source
This paper presents a method to evaluate the exact stationary solution of a single queue with preemptive-resume priorities and finite source. In the case of an infinite source (Poisson arrivals) the solution is given by a well-known simple formula. Models requiring finite customer populations are frequently used for computer performance evaluation (i.e. a processor shared by real time applications), for which the infinite source hypothesis may cause unacceptable errors.
Such a model has already been fully analysed by Jaiswal, but this may yield to very complex computations when applied to real case problems. The same limitation occurs when using a numerical approach. Various approximate solutions have also been proposed.
An exact expression of the utilization factor for each customer population is first proved. A simple iterative algorithm is derived and a PASCAL implementation is described. Several examples are presented.
KeywordsPriority Queue Utilization Factor Preemptive Priority Finite Source Schedule Discipline
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