Energy proportional computing

Energy proportionality is a measure of the relationship between power consumed in a computer system, and the rate at which useful work is done (its utilization, which is one measure of performance). If the overall power consumption is proportional to the computer's utilization, then the machine is said to be energy proportional. Equivalently stated, for an idealized energy proportional computer, the overall energy per operation (a measure of energy efficiency) is constant for all possible workloads and operating conditions. The concept was first proposed in 2007 by Google engineers Luiz André Barroso and Urs Hölzle, who urged computer architects to design servers that would be much more energy efficient for the datacenter setting. Energy proportional computing is currently an area of active research, and has been highlighted as an important design goal for cloud computing. There are many technical challenges remaining in the design of energy proportional computers. Furthermore, the concept of energy proportionality is not inherently restricted to computing. Although countless energy efficiency advances have been made in non-computing disciplines, they have not been evaluated rigorously in terms of their energy proportionality. Energy proportionality is a measure of the relationship between power consumed in a computer system, and the rate at which useful work is done (its utilization, which is one measure of performance). If the overall power consumption is proportional to the computer's utilization, then the machine is said to be energy proportional. Equivalently stated, for an idealized energy proportional computer, the overall energy per operation (a measure of energy efficiency) is constant for all possible workloads and operating conditions. The concept was first proposed in 2007 by Google engineers Luiz André Barroso and Urs Hölzle, who urged computer architects to design servers that would be much more energy efficient for the datacenter setting. Energy proportional computing is currently an area of active research, and has been highlighted as an important design goal for cloud computing. There are many technical challenges remaining in the design of energy proportional computers. Furthermore, the concept of energy proportionality is not inherently restricted to computing. Although countless energy efficiency advances have been made in non-computing disciplines, they have not been evaluated rigorously in terms of their energy proportionality. Sustainable energy is the ideal that society should serve its energy needs without negatively impacting future generations, and which various organizations, governments, and individuals have been advocating. To meet this ideal, efficiency improvements are required in three aspects of the energy ecosystem: