On the design and performance of conventional pipelined architectures

Pipelining is a widely used technique for implementing architectures that have inherent temporal parallelism when there is an operational requirement for high throughput. Many variations on the basic theme have been proposed, with varying degrees of success. The aim of this paper is to present a critical review of conventional pipelined architectures and put some well-known problems in sharp relief. It is argued that conventional pipelined architectures have underlying limitations that can only be dealt with by adopting a different view of pipelining. These limitations are explained in terms of discontinuities in the flow of instructions and data, and representative machines are examined in support of this argument. In a companion paper [Topham, Omondi and Ibbett, 1988] we examine an alternative approach to the design of pipelined architectures and introduce an alternative theory of pipelining, which we call Context Flow.