A New Optoelectronic Hybrid Network Based on Scheduling Optimization of Optical Links

Abstract

The emergence of exascale computers will represent a milestone in high-performance computing (HPC). Optoelectronic interconnections and configurable switches will change the traditional supercomputer architecture. However, new hardware is not easily adapted to dynamic running conditions. Based on scheduling optimization of optical links, we propose a new optoelectronic hybrid network, the software-defined network accelerator (sDNA), for an exascale computer. Our scheduling optimization contains an optical interconnection method and an adaptive routing method. The main contribution of our work is an extended edge forwarding index (E-EFI) optical interconnection method based on slow-switching optical devices. The optical link connections are established by evaluating the traffic offloading revenue for each optical link candidate. To support optical interconnection, sDNA selects a suitable routing strategy according to the job-schedule information and prior HPC application knowledge. We tested sDNA in a network simulator and a prototype exascale computer system using both the US Department of Energy (DOE) application and real-world communication benchmarks. The verification results for traffic offloading reveal that our optical interconnection method not only offloads traffic from electrical links to optical links but also avoids the congestion inherent to electrical links. sDNA maintains a throughput of more than 80 percent bandwidth and reduces the communication delay by 10 percent in our real prototype system and simulator. Thus, sDNA is an ideal candidate for accelerating the communication performance of exascale computers.