Exposing datapath elements to reduce microprocessor energy consumption

Abstract

In this thesis, we evaluate the feasibility of exposing elements in a processor's datapath to the compiler in order to reduce energy consumption. We focus on eliminating register file traffic by exposing the latches in the bypass network, as our study shows that there is potential for significant benefit by doing this. We present the idea of software restart markers to handle the exception management overhead that results from exposing additional processor state. We then implement our proposed techniques and observe an average energy savings of 7.0% across a range of benchmarks when compared to a low-power MIPS processor. We also explore the implications of changing the pipeline structure to both improve performance and expose more machine state.