Functional Self-Testing for Bus-Based Symmetric Multiprocessors

Functional, instruction-based self-testing of microprocessors has emerged as an effective alternative or supplement to other testing approaches, and is progressively adopted by major microprocessor manufacturers. In this paper, we study, for first time, the applicability of functional self-testing on bus-based symmetric multiprocessors (SMP) and the exploitation of SMPs parallelism during testing. We focus on the impact of the memory system architecture and the cache coherency mechanisms on the execution of self-test programs on the processor cores. We propose a generic self-test routines scheduling algorithm aiming at the reduction of the total test application time for the SMP by reducing both bus contention and data cache coherency invalidation. We demonstrate the proposed solutions with detailed experiments in two-core and four-core SMP benchmarks based on a RISC processor core.