XY-turn model for deadlock free routing in honeycomb networks-on-chip

Photonic networks on chip (NoCs) have emerged as the future generation of chip multiprocessors. Routing algorithm is an important aspect to determine the performance of photonic NoCs. In this paper, we have proposed a new model called the XY-turn model for designing partially adaptive or deterministic routing algorithms for honeycomb networks on chip without adding virtual channels. The model prohibits two turns in opposite directions at some particular nodes so that the deadlock can be avoided. The restricted turns result in simplified router architectures especially for photonic NoCs. We have implemented a deterministic routing algorithm based on the new model and it is deadlock free. The simulation is carried out to test the performance of the algorithm in End to End delay and throughput under the conditions that messages length are 128 bytes, 256 bytes and 512 bytes respectively, as well as the network size varies from 36 cores to 64 cores and 98 cores. The results demonstrate that the honeycomb NoCs would benefit from the XY-turn model in terms of communication efficiency.