Exploiting Gray-Box Knowledge of Buffer-Cache Management

The buffer-cache replacement policy of the OS can have a significant impact on the performance of I/O-intensive applications. In this paper, we introduce a simple fingerprinting tool, Dust, which uncovers the replacement policy of the OS. Specifically, we are able to identify how initial access order, recency of access, frequency of access, and long-term history are used to determine which blocks are replaced from the buffer cache. We show that our fingerprinting tool can identify popular replacement policies described in the literature (e.g., FIFO, LRU, LFU, Clock, Random, Segmented FIFO, 2Q, and LRU-K) as well as those found in current systems (e.g., NetBSD, Linux, and Solaris).