ANALYTICALLY MODELING UNRELIABLE PARALLEL PROCESSING SYSTEMS WITH GENERAL TASK TIME DISTRIBUTIONS

For many computing systems, failure is rare enough that it can be ignored. In other systems, failure is so common that the recovery procedure can have a significant impact on the performance of the system. In this paper, assuming a computing system is unreliable, we discuss how heavy-tail or power-tail job completion time distributions can appear in an otherwise well-behaved task stream. This is an important consideration since it is known that powertails can lead to unstable systems. We then demonstrate how to obtain performance and dependability measures for a class of computing systems comprised of P unreliable processors and a finite number of tasks, N, given different recovery policies. Finally, we discuss the effects of checkpointing on the job completion time distribution.