Performance analysis of degradable multiprocessor system using time scale decomposition of GSPNs

A time-scale decomposition (TSD) algorithm of a class of generalized stochastic Petri net (GSPN) models for performance evaluation of degradable multiprocessor systems is presented. The failure and repair rates in a multiprocessor system are an order of magnitude smaller than the rates of job arrival and completion; therefore, the GSPN models of these systems are decomposed into a hierarchical sequence of aggregated subnets, each of which is valid at a certain time scale. These smaller subnets are involved in isolation, and their solutions are combined to get the solution of the whole system. The algorithm is described step-by-step using a simple example. Then a large degradable multiprocessor system, which is intractable using conventional GSPN solution techniques, is analyzed. The complexity of the TSD algorithm is an order of magnitude smaller.<>