Improving Energy Efficiency with Dynamic Compiler-Directed Function Unit Power Control

In this paper, we present a dynamic-compiler-directed approach which adaptively configures CPU´s function units at runtime. It is based on Jikes RVM´s dynamic optimizing compiler and is designed to achieve higher energy efficiency. We describe the implementation to support compiler-controlled adaptive FU and the cost/benefit heuristic of selecting optimization targets to save energy. Our experiment results indicate that this approach achieves about 40% to 65% ALU energy reduction, and reduces the total energy consumption by 6.3% to 14%.