Experimental evaluation of a coarse-grained switch scheduler

Abstract

Modern high performance routers rely on sophisticated interconnection networks to meet ever increasing demands on capacity. Previous studies have used a combination of analysis and idealized simulations to show that coarse-grained scheduling of traffic flows can be effective in preventing interconnect congestion while ensuring high utilization. In this work, we study the performance of a coarse-grained scheduler in a real router with a scalable architecture similar to those found in high performance commercial systems. Our results are obtained by taking fine-grained measurements within the router that provide a detailed picture of the scheduler's behavior under a variety of conditions, giving a more complete and realistic understanding of the short time-scale dynamics than previous studies could provide.