Photonic NoC for DMA Communications in Chip Multiprocessors

As multicore architectures prevail in modern high- performance processor chip design, the communications bottleneck has begun to penetrate on-chip interconnects. With vastly growing numbers of cores and on-chip computation, a high-bandwidth, low-latency, and, perhaps most importantly, low-power communication infrastructure is critically required for next generation chip multiprocessors. Recent remarkable advances in silicon photonics and the integration of photonic elements with standard CMOS processes suggest the use of photonic networks-on-chip. In this paper we review the previously proposed architecture of a hybrid electronic/photonic NoC. We improve the former internally blocking switches by designing a non-blocking photonic switch, and we estimate the optical loss budget and area requirements of a practical NoC implementation based on the new switches. Additionally, we tackle one of the key performance challenges: the latency associated with setting-up photonic paths. Simulations show that the technique suggested can substantially reduce the latency and increase the effective bandwidth. Finally, we consider the DMA communication model in the context of the photonic network and evaluate the optimal DMA block size.