Logically Determined Design: Clockless System Design with NULL Convention Logic

CHAPTER 10

The Shadow Model of Pipeline Behavior

The flow of wavefronts through a logically determined pipeline derives from the behavior of individual cycles and the shared path completeness synchronization among cycles. The flow of elements controlled by local interactions among the elements is an extraordinarily diverse phenomenon and has been studied using extraordinarily diverse models including queueing theory [3,62,38,37], traffic flow models [21], random walk models [14,12], industrial manufacturing production line models [18], and computer pipeline models [16,9,39,5,23]. Helbing [20] provides a comprehensive overview of the approaches to modeling self-driven many particle systems. None of these approaches, however, have generated an intuitively graspable model that illuminates the fundamental mechanism of wavefront flow through a logically determined pipeline structure. The shadow model fills this void.

10.1 PIPELINE STRUCTURE

The primary performance measure for a logically determined pipeline is throughput. The throughput of a cycle is the number of wavefronts that can propagate through a cycle per unit time. The throughput of a pipeline is the number of wavefronts that can propagate through the pipeline per unit time. The pipeline throughput is a result of the individual ...