Colloquium - Pinkston

Interconnection networks are designed to transfer the maximum amount of information within the least amount of time so as not to bottleneck overall system performance. The design and evaluation of interconnection networks should be done from an end-to-end perspective that factors in an understanding of network traffic characteristics. It should include links, interfaces, and traffic demands at the injection and reception endpoints of the network as much as it does topology, switches, and links within the network fabric. Although some rather straightforward performance models have been proposed in the past, many do not consider well the end-to-end and traffic aspects; others are not well suited to enable the network designer to reason about the network tradeoffs being made. This talk will attempt to formulate a very simple, yet general, performance model that provides an upper bound for end-to-end network throughput and allows the designer to reason about various network design tradeoffs and traffic behavior. It is based on the intuitive notion of modeling the network as a "pipe" through which packets are transported end-to-end and determining where the narrowest section or "bottlenecking point" occurs within that pipe. Network topology, deadlock-free routing, arbitration, switching, and flow control are all considered. Application of the model to a few case examples (e.g., the Blue Gene/L and Cell Broadband Engine) are given, along with some empirical validation via cycle-accurate simulation.

Timothy Pinkston is a Professor in the EE-Systems Department of the Viterbi School of Engineering at the University of Southern California, where he heads the SMART Interconnects research group. Since January of 2006, Dr. Pinkston has been serving a 2-year term as a Program Manager in the CCF Division of the CISE Directorate at the National Science Foundation (NSF), where he directs research funding in the Computer System Architecture area of the Computing Processes and Artifacts (CPA) Cluster. His research interests include the development of deadlock-free adaptive routing techniques and on-chip network and router architectures for achieving high-performance communication in multicore and multiprocessor computer systems. Most recently, Dr. Pinkston co-authored a book chapter with Professor José Duato entitled, "Interconnection Networks" which appears as Appendix E in the soon-to-be-released 4th edition of the best-selling text Computer Architecture: A Quantitative Approach, by John Hennessy and David Patterson.