Consistent runtime thermal prediction and control through workload phase detection

Elevated temperatures impact the performance, power consumption, and reliability of processors, which rely on integrated thermal sensors to measure runtime thermal behavior. These thermal measurements are typically inputs to a dynamic thermal management system that controls the operating parameters of the processor and cooling system. The ability to predict future thermal behavior allows a thermal management system to optimize a processor´s operation so as to prevent the on-set of high temperatures. In this paper we propose a new thermal prediction method that leads to consistent results between the thermal models used in prediction and observed thermal sensor measurements, and is capable of accurately predicting temperature behavior with heterogenous workload assignment on a multicore platform. We devise an off-line analysis algorithm that learns a set of thermal models as a function of operating frequency and globally defined workload phases. We incorporate these thermal models into a dynamic voltage and frequency scaling (DVFS) technique that limits the maximum temperature during runtime. We demonstrate the effectiveness of our proposed system in predicting the thermal behavior of a real quad-core processor in response to different workloads. In comparison to a reactive thermal management technique, our predictive method dramatically reduces the number of thermal violations, the magnitude of thermal cycles, and workload runtimes.