A Low Cost Method to Tolerate Soft Errors in the NoC Router Control Plane

In this paper, we propose a low cost method to tolerate soft errors in the main NoC router functional units, i.e., routing units, Virtual Channel (VC) allocators, and switch allocators. The idea behind our proposal is to utilize the idle routing units at neighboring input ports to do redundant Routing Computation (RC) for the local routing requests, and detect errors in the VC Allocation (VA) and Switch Allocation (SA) results by checking if they are consistent with RC results and are in legal states. If required, soft errors are recovered by redoing the failed procedures and retransmitting the flits. Experimental results on an 8x8 2D NoC indicate that: (i) in the routing units, the proposed method requires 38% more silicon real estate than the Sigma & Branch method when XY routing algorithm is used, but it is more general and can be utilized in conjunction with many more routing algorithms; and (ii) in the combined VA/SA units, the proposed method is simpler and more effective than the state of the art methods. When compared with the Triple Modular Redundancy strategy, for similar error detection and correction efficacy, the proposed method can reduce the area and power overhead in routing units by 53% and 38%, respectively, and in combined VA/SA units by 45% and 46%, respectively. The average packet transmission latency increase is less than 5% even if the soft error rate is 0.1/cycle, when compared with that of the baseline router architecture.