Comparative Performance Analysis of Directed Flow Control for Real-Time SCI

摘要

The distributed nature of routing and flow control in a register- insertion ring topology complicates priority enforcement for real-time systems. Two divergent approaches for priority enforcement for ring-based networks are reviewed: a node-oriented scheme called Preemptive Priority Queue and a ring- wide arbitration approach dubbed TRAIN. This paper introduces a hybrid protocol named Directed Flow Control that combines node- and ring-oriented flow control to yield greater performance. A functional comparison of the three protocols as implemented on the Scalable Coherent Interface (SCI) is presented, followed by performance results obtained through high-fidelity modeling and simulation.