Power and frequency analysis for data and control independence in embedded processors

Abstract

In this work we study control independence in embedded processors. We classify control independent instructions to data dependent and data independent and measure each group's frequency and behavior. Moreover, we study how control independent instructions impact power dissipation and resource utilization. We also investigate control independent instructions' behavior for different processors and branch predictors. Our study shows that data independent instructions account for 34% of the control independent instructions in the applications studied here. We also show that control independent instructions account for upto 12% of the processor energy and 15.6%, 11.2% and 8.6% of the instructions fetched, decoded and executed respectively. We also show that control independent instruction frequency increases with register update unit (RUU) size and issue width but shows little sensitivity to branch predictor size. In addition, we illustrate that control independent data independent instructions account for upto 6% of the processor energy. We also show that control independent data independent instruction frequency increases with RUU size and issue width.