A discrete thermal controller for chip-multiprocessors

As the power density of modern processors keeps increasing, thermal management remains a challenging problem for processor designers. Among various solutions, closed-loop automatic thermal controllers have the benefits of fast response speed and high control accuracy. However, as a processor is a discrete system by nature, controllers designed by classic control theories fail to consider the system features related to the discreteness and thus cannot achieve optimal result. In this work, we propose a discrete thermal controller with the form of the digital filter with special concern about the frequency field response affected by the sampling process. We optimize the sampling period and the response time of the controller. Experimental results show up to 50% sampling frequency reduction and up to 25% improvement in the performance of CMP systems with thermal constraints when compared to other state-of-the-art closed-loop thermal controllers.