Coupled Power and Thermal Simulation with Active Cooling

Power is rapidly becoming the primary design constraint for systems ranging from server computers to handhelds. In this paper we study microarchitecture-level coupled power and thermal simulation considering dynamic and leakage power models with temperature and voltage scaling. We develop an accurate temperature-dependent leakage power model and efficient temperature calculation, and show that leakage energy can be different by up to 10X for temperatures between 35°C and 110°C. Given the growing significance of leakage power and its sensitive dependence on temperature, no power simulation without considering dynamic temperature calculation is accurate. Furthermore, we discuss the thermal runaway induced by the interdependence between leakage power and temperature, and show that in the near future thermal runaway could be a severe problem. We also study the microarchitecture level coupled power and thermal management by novel active cooling techniques that reduce packaging thermal resistance. We show that the direct water-spray cooling technique reduces thermal resistance from 0.8°C/W for conventional packaging to 0.05°C/W, and increases system maximum clock by up to 2.44X under the same thermal constraints.