Increasing processor performance by implementing deeper pipelines

Abstract

One architectural method for increasing processor performance involves increasing the frequency by implementing deeper pipelines. This paper will explore the relationship between performance and pipeline depth using a Pentium® 4 processor like architecture as a baseline and will show that deeper pipelines can continue to increase performance.This paper will show that the branch misprediction latency is the single largest contributor to performance degradation as pipelines are stretched, and therefore branch prediction and fast branch recovery will continue to increase in importance. We will also show that higher performance cores, implemented with longer pipelines for example, will put more pressure on the memory system, and therefore require larger on-chip caches. Finally, we will show that in the same process technology, designing deeper pipelines can increase the processor frequency by 100%, which, when combined with larger on-chip caches can yield performance improvements of 35% to 90% over a Pentium® 4 like processor.