HotSpot Cache: Saving I-Cache Energy with Dynamic Program Hot Spot Detection for Multimedia Applications

Power consumption is an important design issue of current embedded systems. It has been shown that instruction cache accounts for a signicant portion of the power dissipation of the whole chip. Several studies have proposed to add a cache (L0 cache) that is very small relative to the conventional L1 cache on chip for power optimization since a smaller cache has lower load capacitance. However, energy savings often come at the cost of performance degradation. In this paper, we propose a mech- anism that detects program hot spots dynamically & stores only hot spots in the L0 cache. The optimization goal is to achieve high L0 cache utilization without sacricing performance. We design a run-time hot-spot detection mechanism around the Branch Target Buer. The results show up to 57 % energy reduction without performance degradation for a set of multimedia applications