A segment-based DSM supporting large shared object space

This paper introduces a software DSM that can extend its shared object space exceeding 4GB in a 32-bit commodity cluster environment. This is achieved through the dynamic memory mapping mechanism, with local hard disks as backing store. We introduce the new concept of segments with intelligent splitting to reduce network traffic, false sharing as well as adapt better to the shared memory access patterns. A priority-based swapping algorithm is designed to reduce disk accesses for efficient dynamic memory mapping, and maximize the use of disk space as shared object space. A new queue-based scheme is also devised for efficient and simple management of memory blocks. The proposed solutions were implemented in LOTS V.2, and it can outperform its previous version when running small applications, while the maximum shared object space is increased to one-third of the total free disk space available among all the nodes.