Algorithms for reconfiguring NoC-based fault-tolerant multiprocessor arrays

Abstract

This paper investigates the techniques to construct high-quality target processor array (fault-free logical subarray) from a physical array with faulty processing elements (PEs), where a fixed number of spare PEs are pre-integrated that can be used to replace the faulty ones when necessary. A reconfiguration algorithm is successfully developed based on our proposed novel shifting operations that can efficiently select proper spare PEs to replace the faulty ones. Then, the initial target array is further refined by a carefully designed tabu search algorithm. We also consider the problem of constructing a fault-free subarray with given size, instead of the original size, which is often required in energy-efficient MPSoC design. We propose two efficient heuristic algorithms to construct target arrays of given sizes leveraging a sliding window on the physical array. Simulation results show that the improvements of the proposed algorithms over the state of the art are 19% and 16%, in terms of congestion factor and distance factor, respectively, for the case that all faulty PEs can be replaced using the spare ones. For the case of finding 64×64 target array on 128×128 host array, the proposed heuristic algorithm saves the running time up to 99% while the solution quality keeps nearly unchanged, in comparison with the baseline algorithms.