Comparative performance analysis of directed flow control for real-time SCI

The distributed nature of routing and flow control in a register-insertion ring topology complicates priority enforcement for real-time systems. Two d ivergent approaches for priority enforcement for ring-based networks are re viewed: a node-oriented scheme called preemptive priority queue and a ring- wide arbitration approach dubbed TRAIN. This paper introduces a hybrid prot ocol 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 is presented, followed by performance results obtained through high-fidelity modeling and simulation. (C) 2001 Elsevier Science B.V. All rights reserved.