Where does the power go in a computer system: Experimental analysis and implications

Abstract

In the last few years the power dissipation problem of computer systems has attracted more and more attention. A lot of work has been done to decrease power dissipation and increase energy efficiency. We are still, however, not observing significant decrease of power dissipation. On the contrary, modern computer systems consume ever increasing amounts of energy. Where does the power go in a computer system is a question that many people are concerned with. Through comprehensive experiments and measurements, we observe several phenomenons that are in opposition to our common sense. Many people believe, for instance, that CPU utilization is a good indicator of the power dissipation of CPU. Our experiment results, however, show that CPU utilization is not an accurate reflection of the CPU power. Moreover, we discover that despite the performance improvements it introduces, cache could be a big problem for power reducing. Based on our observations we derive ten implications that are important for energy efficient system design.