Packet logging mechanism for adaptive online fault detection on Network-on-Chip

The shrinking size of transistors and smaller interconnect elements contribute to higher probability of on-chip faults. In order to sustain the functionality of a system in the presence of faults, fault tolerance becomes one of the key feature in Network-on-Chip (NoC) design methodology. Existing end-to-end (E2E) error detection and correction (EDC) performs well at low error rate whereas switch-to-switch (S2S) EDC performs better at high error rate. Nonetheless, choosing between both techniques is required with changing fault occurrence probability. This paper proposes an adaptive online fault detection based on packet logging mechanism. In this proposed mechanism, each router logs transmitted packets and NACK packets as well as monitors its fault level continuously. Then, the router will determine either to use E2E or S2S EDC based on error probability. Based on experimental results, our proposed adaptive method switches between E2E or S2S relative to error probability performs better than only E2E or S2S.