According to two related recent studies [1,2], energy consumption cost contributes to more than 12% of overall data center cost and is the fastest growing component of the operating cost. The same studies also point out that data centers consume only 15% energy in actual processing, while the rest of the energy is used by the cooling equipment. Cooling infrastructure adds a significant overhead to the operating cost in terms of power consumption as well as system management. In addition,

according to [2], the data center industry accounts for the 2% of global CO2 emission, which is at the same level as the emission introduced by the aviation industry. Therefore, it is clear that improving power consumption will have a significant influence on the cost effectiveness, reliability, and environmental impact of current and future distributed systems. Consequently, extensive research effort has been recently directed toward developing power-efficient computing systems, also referred to as “power-aware” systems.