Smart cache: an energy-efficient D-cache for a software MPEG-2 video decoder

Power consumption is an important design issue of current embedded systems. Data caches consume a significant portion of total processor power for data intensive applications. In this paper, we propose to utilize application-specific information for cache resource allocation to achieve energy saving, including cache bypassing, the mini-cache and way-partition. We use a software MPEG-2 video decoder as our first targeted application. Cache bypassing excludes data types that have little reuse from the L1 cache. The mini-cache stores data types with high access frequency and small memory footprints to a small on-chip memory area. The way-partition mechanism maps program data structures to different ways of caches and enables only the matching ways on each access. The results show up to 40% of cache energy reduction without sacrificing performance.