Improving energy efficiency of configurable caches via temperature-aware configuration selection

Active power used to be the primary contributor to total power dissipation of CMOS designs, but with the technology scaling, the share of leakage in total power consumption of digital systems continues to grow. Temperature is another factor that exponentially increases the leakage current. In this paper, we show the effect of temperature on the optimal (minimum-energy-consuming) cache configuration for low energy embedded systems. Our results show that for a given application and technology, the optimal cache size moves toward smaller caches at higher temperatures, due to the larger leakage. Our results show that using a Temperature-Aware Configurable Cache (TACC), up to 61% energy can be saved for instruction cache and 77% for data cache compared to a configurable cache that has been configured for only the corner case temperature (100°C). The TACC also enhances the performance by up to 28% and 17% for the instruction and data cache, respectively.