Thermal-Aware Clustered Microarchitectures

As frequencies and feature size scale faster than operating voltages, power density is increasing in each processor generation. Power density and the cost of removing the heat it generates are increasing at the same rate. Leakage is significantly increasing every process generation and it is expected to be the main source of power in the near future. Moreover, leakage power grows exponentially with temperature. This paper proposes and evaluates several techniques with two goals: reduction of average temperature in order to decrease leakage power, and reduction of peak temperature in order to reduce cooling cost. Combinations of temperature-aware steering techniques and cluster hopping are investigated in a quad-cluster superscalar microarchitecture. Combining cluster hopping with a temperature-aware steering policy results in 30% reduction in leakage power and 8% reduction in average peak temperature at the expense of a slowdown of just 5%.