The design and analysis of distributed virtual memory consistency protocols in an object oriented operating system

Abstract

An object-orientated framework for the design of distributed virtual memory consistency protocols is presented. It is shown that custom designed protocols for different types of applications are easy to construct and use within this framework. Consistency protocols are shown to be useful in implementing atomic updates, and in controlling the assignment of pages to process. An analysis of the performance of the Choices distributed virtual memory implementation is presented. It is shown that distributed virtual memory improves the performance of many applications by separating , and distributing the tasks of process management, synchronisation and paging. This performance improvement occurs despite the overhead in setting up and maintaining the coherence across the network. This is particularly noticeable when more processes than processors are active on a node. The results presented illustrate the effective improvements that can be achieved using correct coherence protocol and the current hardware restrictions limiting the performance of distributed virtual memory. In this it suggests further areas for research.