An Implementation Study of a Detection-Based Adaptive Block Replacement Scheme

Recent research has shown that near optimal performance can be achieved by utilizing userlevel hints of block reference patterns of applications. However, obtaining user-level hints may not always be possible and/or the provided hints may not be accurate leading to sub-optimal performance. In this paper, we propose a new adaptive buffer management scheme called DEAR (DEtection based Adaptive Replacement) that automatically detects the block reference patterns of applications without any user intervention. The DEAR scheme uses a periodic process and the detection is made by associating block attribute values such as backward distance and frequency gathered at the (i \Gamma 1)-th invocation with forward distances of blocks referenced between the (i \Gamma 1)-th and i-th invocations. Based on the detected reference pattern, the proposed DEAR scheme applies an appropriate replacement policy to each application. We implemented the DEAR scheme in FreeBSD 2.2.5 and measured its performance us..