Towards energy proportionality in web systems

Green computing is a topic that receives a great amount of interests in the past few years. Energy proportionality is a principal of ensuring energy consumption is proportional to the system workload. Energy proportional design can effectively improve energy efficiency in computing systems. In this paper, we present an energy proportional model based on queuing theory and service differentiation in server clusters. The presented scheme provides controllable and predictable quantitative control of power consumption with theoretically guaranteed service performance. The preliminary simulation results indicate the effectiveness and limitations of the energy proportional model under different workloads and energy consumption curves. The most interesting finding in this paper is the trade-off between energy and performance in cluster systems.