Physical aware frequency selection for dynamic thermal management in multi-core systems

In order to maintain performance per Watt in microprocessors, there is a shift towards the chip level multiprocessing paradigm. Microprocessor manufacturers are experimenting with tens of cores, forecasting the arrival of hundreds of cores per single processor die in the near future. With such large-scale integration and increasing power densities, thermal management continues to be a significant design effort to maintain performance and reliability in modem process technologies. In this paper, we present two mechanisms to perform frequency scaling as part of Dynamic Frequency and Voltage Scaling (DVFS) to assist Dynamic Thermal Management (DTM). Our frequency selection algorithms incorporate the physical interaction of the cores on a large-scale system onto the emergency intervention mechanisms for temperature reduction of the hotspot, while aiming to minimize the performance impact of frequency scaling on the core that is in thermal emergency. Our results show that our algorithm consistently succeeds in maximizing the operating frequency of the most critical core while successfully relieving the thermal emergency of the core. A comparison of our two alternative techniques reveals that our physical aware criticality-based algorithm results in 11.7% faster clock frequencies compared to our aggressive scaling algorithm. We also show that our technique is extremely fast and is suited for real time thermal management.