Adaptive cache compression for non-volatile memories in embedded system

Cache compression has been studied to increase the effective cache size by storing the cache blocks in a compressed form in the cache. However, it also generates additional write operations during the compressing and compacting of cache blocks. Since increasing the write operations leads to a surging of dynamic energy consumption and a shortening of the lifetime of the cache in the Non-Volatile Memory (NVM) based Last-Level Cache (LLC), it is needed to balance the extra write operations against the performance improvement. In this paper, we identify that cache compression is not always efficient for NVM-based LLC. In light of the analysis, we propose Adaptive Cache Compression for NVM (ACCNVM) whose cache block is only compressed when cache compression is efficient. The result shows that our proposal achieves a 16.4% energy savings and a 19.1% lifetime extension with respect to the cache, which uses a state-of-the-art cache compression scheme.