Design of Fault-Tolerant Router for 3D NoC Based on Virtual Channel Fault Granularity Partition

Routers become subject to physical manufacture defects and running-time vulnerability in the deep submicron technology, which results in virtual channel permanent faults. The faults affect the performance and functionality of systems and result in communication malfunctions. In order to tolerate virtual channel faults effectively, and to ensure system performance and efficient usage of available resources, the type of failure is subdivided into coarse-grained fault and fine-grained fault, and then we propose the SVS router (single virtual channel sharing router) architecture to achieve a single virtual channel sharing between ports in the same group, which contains two ports in the router. Coarse-grained faults are tolerated by using adjacent ports' shared virtual channel in the same group. According to the information of Slot State Table, fine-grained faults are tolerated by configuring read/write pointer value to skip fault buffer slots. Also, in the absence of coarse-grained fault condition, shared virtual channel can be used for load balancing and fault tolerance of calculation module. Experimental results demonstrate significant reduction in average packet latency, and improvement in throughput under three different fault conditions compared with other existing virtual channel architectures. It shows that this scheme effectively improves system reliability, ensures system performance and makes full use of the available resources.