Tools for the Development of Application - Speci cVirtual Memory

While many applications incur few page faults, some scientiic and database applications perform poorly when running on top of a traditional virtual memory implementation. To help address this problem, several systems have been built to allow each program the ex-ibility to use its own application-speciic page replacement policy, in place of the generic policy provided by the operating system. This has the potential to improve performance for the class of applications limited by virtual memory behavior; however, to realize this performance gain, application developers must re-implement much of the virtual memory system, a non-trivial programming task. Our goal is to make it easy for programmers to develop new application-speciic page replacement policies. To do this, we have implemented (i) an extensible object-oriented user-level virtual memory system and (ii) a graphical performance monitor for virtual memory behavior. Together, these help the user to identify problems with an application's existing paging policy and to quickly modify the system to x these problems. We have used our tools for tuning the virtual memory performance of several applications; we present one case study illustrating the beneets and the limitations of our tools.