A measure of graceful degradation in parallel-computer systems

Gracefully-degrading multiprocessor systems are studied using a multistage interconnection-network-based parallel computer as an example. A measure of graceful degradation, system functionality, is used and analyzed; it is proportional to the number of data-flow paths in a system in the presence of faults. Each path consists of a processor, switches, and a memory. Under this approach, graceful degradation of a multiprocessor system can be evaluated as a combination of individual degradations in each of the processor, memory, and network subsystems. A detailed evaluation of graceful degradation of tightly coupled multiprocessor systems (of large size) based on multistage interconnection networks is given