Time Division Multiplexing of Optical Interconnection Networks

本研究的目标是研究、设计和评估多处理器应用中的时分复用光互连网络的控制机制。这种机制将相对较慢的网络控制与较高的光数据传输带宽分离。这项研究将评估时分复用的优势、能力和局限性。具体地说，将开发模型来指定应用的通信需求，表达和测量通信负载中存在的通信局部性，并估计多路复用互连网络中的通信成本。不同的控制协议将在从实际并行应用中收集的轨迹上以及在通信局部性模型的帮助下生成的合成轨迹上进行模拟和测试。对集中式、分布式和流水线控制策略进行了实施和比较。这个项目的动机是几个观察结果。首先，在没有多路复用的情况下，在网络中建立端到端连接的控制开销可能是令人望而却步的。其次，应用程序表现出通信局部性，这放大了多路传输的好处。第三，光路的高带宽允许在对单个连接上的传输速率影响最小的情况下进行多路复用。最后，大规模并行程序的性质允许编译器利用当前技术确定满足大多数通信要求的多路复用序列。

The goal of this research is to study, design and evaluate control mechanisms for time-multiplexing optical interconnection networks in multiprocessor applications. Such mechanisms decouple the relatively slow network control from the high optical data transmission bandwidth. The research will assess the advantages, capabilities and limitations of time-division multiplexing. Specifically, models will be developed to specify the communication requirements of applications, to express and measure the communication locality present in communication loads, and to estimate the communication cost in multiplexed interconnection networks. Different control protocols will be simulated and tested on traces collected from actual parallel applications, and on synthetic traces generated with the help of the communication locality model. Centralized, distributed and pipelined control strategies will be implemented and compared. This project is motivated by several observations. First, without multiplexing, the control overhead of establishing end-to-end connections in a network may be prohibitive. Second, applications exhibit communication locality which amplifies the benefits of multiplexing. Third, the high bandwidth of optical paths allows for multiplexing with minimal effect on the transmission rate on individual connections. Finally, the nature of massively parallel programs allows compilers to determine, with current technology, the multiplexing sequences that satisfy most of the communication requirements.