Fixed Segmented LRU cache replacement scheme with selective caching

Cache replacement policies are an essential part of the memory hierarchy used to bridge the gap in speed between CPU and memory. Most of the cache replacement algorithms that can perform significantly better than LRU (Least Recently Used) replacement policy come at the cost of large hardware requirements [1][3]. With the rise of mobile computing and system-on-chip technology, these hardware costs are not acceptable. The goal of this research is to design a low cost cache replacement algorithm that achieves comparable performance to existing scheme. In this paper, we propose two enhancements to the SLRU (Segmented LRU) algorithm: (i) fixing the number of protected and probationary segments based on effective segmentation ratio with increasing the protected segments, and (ii) implementing selective caching, to achieve more effective eviction, based on preventing dead blocks from entering the cache. Our experiment results show that we achieve a speed up to 14.0% over LRU and up to 12.5% over standard SLRU.