Performance/Availability Model of Shared Resource Multiprocessors

Shared-resource systems are particularly vulnerable to faults which contaminate the shared-resource, and result eventually in system failure. In shared-memory computer systems, resource guardians can provide some protection. A model is developed which incorporates both a performance and availability measure of a general gracefully-degradable shared-resource multiprocessor. Various system parameters are studied and their effects are compared on the basis of a performance/cost ratio. As the number of processors increases or as the reliability of a processor or memory module decreases, some resource protection becomes neccessary. There is a class of systems for which adding resource protection provides no measurable benefit.