Evaluation of design options for the trace cache fetch mechanism

Abstract

In this paper, we examine some critical design features of a trace cache fetch engine for a 16-wide issue processor and evaluate their effects on performance. We evaluate path associativity, partial matching, and inactive issue, all of which are straightforward extensions to the trace cache. We examine features such as the fill unit and branch predictor design. In our final analysis, we show that the trace cache mechanism attains a 28 percent performance improvement over an aggressive single block fetch mechanism and a 15 percent improvement over a sequential multiblock mechanism.