Small-LRU: A Hardware Efficient Hybrid Replacement Policy

Replacement policy plays a major role in improving the performance of the modern highly associative cache memo-ries. As the demand of data intensive application is increasing it is highly required that the size of the Last Level Cache (LLC) must be increased. Increasing the size of the LLC also increases the associativity of the cache. Modern LLCs are divided into multiple banks where each bank is a set-associative cache. The replacement policy implemented on such highly associative banks consume significant hardware (storage and area) overhead. Also the Least Recently Used (LRU) based replacement policy has an issue of dead blocks. A block in the cache is called dead, if the block is not used in the future before its eviction from the cache. In LRU policy, a dead block can not be remove early until it become LRU-block. So, we have proposed a replacement technique which is capable of removing dead block early with reduced hardware cost between 77% to 91% in comparison to baseline techniques. In this policy random replacement is used for 70% ways and LRU is applied for rest of the ways. The early eviction of dead blocks also improves the performance of the system by 5%.

@article{Das2020,
  title     = {Small-LRU: A Hardware Efficient Hybrid Replacement Policy},
  journal   = {International Journal of Advanced Computer Science and Applications},
  volume    = {11},
  number    = {9},
  year      = {2020},
  publisher = {The Science and Information Organization},
  author    = {Purnendu Das and Bishwa Ranjan Roy},
  doi       = {10.14569/IJACSA.2020.0110981},
  url       = {https://doi.org/10.14569/IJACSA.2020.0110981}
}