Performance Evaluation of Probe-Send Fault-tolerant Network-on-chip Router

With increasing reliability concerns for current and next generation VLSI technologies, fault-tolerance is fast becoming an integral part of system-on-chip and multi-core architectures. Another trend for such architectures is network-on-chip (NoC) becoming a standard for on-chip global communication. In an earlier work, a generic fault-tolerant routing algorithm in the context of NoCs has been presented. The proposed routing algorithm works in two phases, namely path exploration (PE) and normal communication. This paper presents fundamental insights into various novel PE approaches, their feasibility and performance trade-offs for k-ary 2-cube NoCs. The dependence of the normal communication phase on the probability of finding paths and their quality in the first phase emphasizes the PE´s significance. One major contribution of this work is the investigation of application of constrained randomness to PE for optimizing the quality of paths. Another contribution is the proposed use of merging of traffic to reduce the reconfiguration time by a large amount (73.8% on an average).