Replacement Policy for Prefetched data

The most widely used data structure for cache replacement policy is LRU, mainly because of its simplicity. This policy leverages temporal locality in the workload to improve cache hit ratios. Even within sequentially prefetched data, it is possible to have non-sequential accesses that exhibit temporal locality. This has encouraged most commercial systems to use the LRU data structure and replacement policy even for prefetched data rather than simply evicting prefetched data immediately after use. In this paper, we improve this LRU policy by making it aware of the difference between prefetched and demand-paged data. A prefetched page is moved to the most recently used (MRU) position only on repeated access and not on the first access.