FAULT-TOLERANCE ANALYSIS OF HYPERCUBE SYSTEMS USING PETRI NET THEORY

Studies of performance disregarding reliability or reliability ignoring performance do not give a complete picture of the capability of parallel /distributed systems. However, a combined study of performance and reliability (performability) is becoming increasingly important in evaluating the behavior of such systems. In this article, we propose a technique to model and analyze the performability of parallel and distributed architectures using generalized stochastic Petri nets (GSPNs). This technique consists of 1) a GSPN performance model, 2) a GSPN reliability model, and 3) a method for combining a Markov reliability model with the metrics of the performance model. We illustrate use of the proposed technique by first modeling and analyzing the performance of an Intel personal super computer (iPSC) /2 hypercube system under the work-load of a concurrent matrix multiplication algorithm. Next, a reliability model based on a subcube reliability approach in the presence of multiple faults with and without repair (or coverage) is modeled and analyzed. Finally, various performability measures for the hypercube architecture are presented. To refine the performability model, a parametric sensitivity analysis is presented.