Abstract

Wormhole routing in mesh-connected networks can be deadlock free and adaptive without the addition of channels to the basic topologies. Previous routing algorithms for meshes have been either deadlock free and nonadaptive or deadlock free and adaptive at the expense of adding physical or virtual channels. Our model for designing adaptive, deadlock-free routing algorithms is based on analyzing the directions in which packets can turn in a mesh. Prohibiting just a quarter of the turns in a 2D or 3D mesh can prevent packets from waiting in cycles. The remaining three quarters of the turns permit partial adaptiveness in routing. We describe several of the resulting routing algorithms, prove that they are deadlock free, and simulate them under a variety of conditions. Simulations of policies for selecting input channels show that transmitting extra information in the header flits can reduce communication latencies at high network throughputs. Simulations of policies for selecting output cha...

Citations