Approximate MVA solutions with fixed throughput classes

Abstract

Transaction (open) type workloads are often used in approximating computer system workloads which are actually closed because open workloads provide reasonable estimates in many cases and their solutions are straight-forward. We have found that their use can distort the results for many workloads in a multiclass queueing network model of a computer system. We have replaced transaction workloads with what we call fixed class workloads. We present an approximate algorithm based on MVA that represents a class with a given throughput by a corresponding terminal or batch class, which we call a fixed class workload. We solve for the closed population required to deliver the requested throughput. We also present techniques for overcoming problems encountered in the solution of some fixed class models.