Application-Oriented On-Board Optical Technologies for HPCs

The increased communication bandwidth demands of high performance computing (HPC) systems calling at the same time for reduced latency and increased power efficiency have designated optical interconnects as the key technology in order to achieve the target of exascale performance. In this realm, technology advances have to be accompanied by the development of corresponding design and simulation tools that support end-to-end system modeling in order to evaluate the performance benefits offered by optical components at system scale. In this paper, we present recent advances on electro-optical printed circuit boards (EOPCB) technology development pursued within the European FP7 PhoxTroT research program and directed toward system-scale performance benefits in real HPC workload applications. We report on high-density and multilayered EOPCBs together with all necessary building blocks for enabling true optical blade technology, including multimode polymer-based single- and dual-layer EOPCBs, a board-compatible optically interfaced router chip, and passive board-level connectors. We also demonstrate a complete optical blade design and evaluation software simulation framework called OptoHPC that tailors optical blade technology development toward optimized performance at HPC system scale, allowing for its validation with synthetic workload benchmark traffic profiles and for reliable comparison with existing HPC platforms. The OptoHPC simulator is finally utilized for evaluating and comparing a 384-node HPC system relying on optically enabled blades with the state-of-the-art Cray XK7 HPC network when performing with a range of synthetic workload traffic profiles, revealing the significant throughput and delay improvements that can be released through application-oriented optical blade technology.