Expression of Concern: Provisioning On-Chip Networks under Buffered RC Interconnect Delay Variations

A Network-on-Chip (NoC) replaces on-chip communication implemented by point-to-point interconnects in a multi-core environment by a set of shared interconnects connected through programmable crosspoints. Since an NoC may provide a number of paths between a given source and destination, manufacturing or runtime faults on one interconnect does not necessarily render the chip useless. It is partly because of this fault tolerance that NoCs have emerged as a viable alternative for implementing communication between functional units of a chip in the nanometer regime, where high defect rates are prevalent. In this paper, we quantify the fault tolerance offered by an NoC against process variations. Specifically, we develop an analytical model for the probability of failure in buffered global NoC links due to interconnect dishing, and effective channel length variation. Using the developed probability model, we study the impact of link failure on the number of cycles required to establish communications in NoC applications.