Computing in Networks: Active System Area Networks

计算和通信的融合产生了基于网络的应用的爆炸性增长。可以从基于Web的应用程序、交互式模拟、游戏、可视化和协作环境中提取大量的例子。当前开发基于网络的应用的方法仍然基于以CPU为中心的模型，使用针对单处理器或小规模多处理器应用而优化的节点体系结构。这可能会导致分布式应用程序的效率显著降低。该项目探索了一种支持新兴的基于网络的应用程序的体系结构，其中选定的应用层计算在网络接口(NIS)内执行。重点放在(现在)作为一种可行的高性能计算工具出现的工作站网络上。在此背景下，该项目将支持具有大量计算和数据处理要求的应用程序。这样的高性能程序来自三个不同的应用领域：科学模拟、计算机视觉和图像处理以及计算机图形学。支持这类程序的方法的独特之处在于使用了可扩展的网络接口，其中扩展涉及在NIS上的低成本微处理器上执行的程序，以及在现场可编程门阵列(FGA)形式的附加、可编程和NI相关硬件上执行的程序。具体地说，该项目将演示(1)使用现场可编程门阵列来实现数据密集型计算，以及(2)使用NIS的微处理器来处理相关的元信息，并执行计算上非密集型的操作，最好是在网络附近执行。NIS的可扩展性将通过开发灵活且可扩展的虚拟通信机来实现。该项目指的是诸如主动系统区域网络(ASAN)之类的增强型网络。关键研究问题是：(1)了解和证明ASAN比主机CPU更有效地执行选定的计算和服务的能力，并探索将某些功能从主机CPU转移到ASAN的效果和权衡；(2)开发编程模型，使ASAN的计算资源能够高效地和特定于应用的使用；(3)创建一个低开销和易于扩展的ASSAN软件体系结构。它包括构建测试床、实现选定的NI扩展以供本工作中研究的三类并行/分布式应用程序使用，以及对所产生的系统/应用程序性能进行性能评估。该方法的成功演示将对未来多媒体网络应用的设计、优化和支持方式产生重大影响。

The confluence of computing and communication has produced an explosion of network-based applications. Numerous examples can be drawn from web-based applications, interactive simulations, gaming,visualization, and collaborative environments. Current approaches to the development of network-based applications are still based on a CPU-centric model using node architectures optimized for uniprocessoror small-scale multiprocessor applications. This can lead to significant inefficiencies for distributed applications.This project explores an architecture for the support of emerging network-based applications whereby selected application-level computations are executed within network interfaces (NIs). The focus is onnetworks of workstations (NOW) that have emerged as a viable high performance computational vehicle. Within this context the project will support applications with substantial computation and data manipulationrequirements. Such high performance programs are drawn from three different application domains: scientific simulation, computer vision and image processing, and computer graphics. The unique aspect of theapproach to supporting these classes of programs is the use of extensible network interfaces, where extension concerns programs executed both on the low cost microprocessors resident on NIs and on additional, programmable and NI-associated hardware in the form of field programmable gate arrays (FPGAs). Specifically, the project will demonstrate (1) the use of FPGAs to implement data-intensivecomputations and (2) the use of the NIs' microprocessors to handle associated meta-information and perform computationally non-intensive operations best performed "close" to the network. Extensibility for NIs will be attained by development of a flexible and extensible virtual communication machine. The project refers to such enhanced networks as Active System Area Networks (ASANs).The key research issues are (1) to understand and demonstrate an ASAN's ability to perform selected computations and services more efficiently than host CPUs and to explore the effects and trade-offs of off-loading certain functionality from host CPUs to the ASAN, (2) to develop the programming model that enables the efficient and application-specific use of the ASAN's computational resources, and (3) to create an ASAN software architecture that is low overhead and easily extensible.The approach to the proposed research is experimental. It includes construction of a testbed, implementation of selected NI extensions for use by the three classes of parallel/distributed applications investigated in this work and performance evaluation of the resulting system/application performance. Successful demonstration of theapproach will have a major impact the way future multimedia network applications are designed, optimized, and supported.