Effects of resource request patterns in queueing network models

Queueing network models of computing systems are becoming increasingly popular because of their robustness and ease of solution. The impact of resource request patterning upon these models is presently not well understood. This paper proves the counter-intuitive fact that the effect of both holding time and routing patterning upon the performance measures for the important class of local balance models is nil. A study of a larger class of models, over a parameter space typical of models of computing systems, reveals that the impact of patterning of resource requests upon performance measures is negligible. This conclusion has important consequences for understanding the robustness of queueing network models of computing systems and for the level of detail necessary for accurate workload characterization. The practical consequences of this result to performance analysis of computing systems are considered. 4 figures, 5 tables.