ColdBus: A Near-Optimal Power Efficient Optical Bus

High static power dissipation is one of the largest hurdles in the widespread adoption of on-chip optical networks. There are numerous proposals in literature for the reduction of static power by predicting the activity in future time intervals, and then powering off the laser, and also by sharing optical bandwidth. We propose a novel scheme called ColdBus in this paper that introduces a new method of predicting the optical NoC traffic using program counter addresses, moreover, we then propose novel structures and predictors for handling mispredictions. These units allow optical transmitters to share bandwidth between them while simultaneously minimizing static power. We show that ColdBus consumes 4.1X less optical power than other state of the art proposals. It additionally has a speedup of 3.1%, and improves ED2 by 18% for a suite of Splash, Parsec, and Parboil benchmarks.