Predicting communication protocol performance on superscalar architectures using instruction dependency

Increasing diversity in telecommunication workloads leads to greater complexity in communication protocols. This occurs as channel bandwidth rapidly increases. These factors result in larger computational loads for network processors that are increasingly turning to high performance microprocessor designs. This paper presents an analytical method for estimating the performance of instruction level parallel (ILP) processors executing network protocol processing applications. Instruction dependency information extracted while executing an application is used to calculate upper and lower bounds for throughput, measured in instructions per cycle (IPC). Results using UDP/TCP/IP applications show that the simulated IPC values fall between the analytically derived upper and lower bounds, validating the model. The analytical method is much less expensive than cycle-accurate simulation, but reveals similar throughput performance predictions. This allows the architectural design space for network superscalar processors to be explored more rapidly and comprehensively, to reveal the maximum IPC that is possible for a given application workload and the available hardware resources.