An object-oriented framework for experimenting with alternative process architectures for parallelizing communication subsystems

The demand for high-performance distributed communication systems (such as video-on-demand servers, global personal communication systems, and the underlying communication protocol stacks) is increasing dramatically. Distributing communication services throughout high-speed computer networks offers many potential benefits by increasing performance, scalability, and functionality. In particular, performing communication services in parallel helps to improve performance by increasing processing rates and reducing latency. To improve performance significantly, however, the speed-up obtained from parallel processing must outweigh the major sources of overhead associated with parallel processing. On multi-processor platforms based on shared memory (rather than message passing), these sources of overhead primarily involve context switching, synchronization, and data movement.; Many communication systems (such as the layered protocol stacks specified by the TCP/IP and the ISO OSI reference models) decompose naturally into a series of hierarchically-related tasks. A number of process architectures have been proposed as the basis for parallelizing these types of communication systems in order to improve performance. There are two fundamental types of process architectures: task-based and message-based. Task-based process architectures are formed by binding one or more processing elements to the layers of tasks in a communication system. In contrast, message-based process architectures are formed by binding the processing elements to the data messages and control messages that flow through the layers of tasks. Each type of process architecture incurs different levels of context switching, synchronization, and data movement overhead. This overhead is affected by factors such as the application requirements, OS and hardware platform, and network characteristics.; This dissertation describes parallel process architecture performance experiments conducted using the ADAPTIVE Service eXecutive (ASX) framework. The purpose of this research is to identify architectures for structuring parallelism to reduce the overhead incurred on shared memory multi-processing platforms. The ASX framework facilitates the flexible configuration of high-performance distributed communication systems that effectively utilize parallelism on shared memory multi-processor platforms. The ASX framework controls for a number of relevant confounding factors (such as application and protocol functionality, concurrency control schemes, and application traffic characteristics). By controlling these factors, the ASX framework enables precise measurement of the performance impact of alternative process architectures for parallelizing communication protocol stacks. The dissertation describes the object-oriented architecture of the ASX framework and presents results from the process architecture performance experiments.