Cache replacement algorithms have focused on managing caches that are in the datapath. In datapath caches, every cache miss results in a cache update. Cache updates are expensive because they induce cache insertion and cache eviction overheads which can be detrimental to both cache performance and cache device lifetime. Non-datapath caches, such as host-side flash caches, allow the flexibility of not having to update the cache on each miss. We propose the multi-modal adaptive replacement cache (mARC), a new cache replacement algorithm that extends the adaptive replacement cache (ARC) algorithm for non-datapath caches. Our initial trace-driven simulation experiments suggest that mARC improves the cache performance over ARC while significantly reducing the number of cache updates for two sets of storage I/O workloads from MSR Cambridge and FIU.
