Traditional file systems do not allow applications to control file caching replacement decisions. We have implemented two-level replacement, a scheme that allows applications to control their own cache replacement, while letting the kernel control the allocation of cache space among processes. We let applications choose from a menu of common policies that are implemented in the kernel. This is effective and requires low overhead. We demonstrate that for applications with large data sets, the combination of good application-chosen replacement policies, and our kernel allocation policy LRU-SP, can improve performance significantly. We also show that LRU-SP is crucial to the performance improvement for multiple concurrent applications: LRU-SP fairly distributes cache blocks and offers protection against foolish applications.

This technical report has been published as

Implementation and Performance of Application-Controlled File Caching. pei Cao, Edward W. Felten and Kai Li, Proc. of 1st Symposium on Operating Systems Design and Implementation, pp. 165-178, November 1994.