The evaluation of user-level software based distributed shared memory systems

Distributed systems on computer networks have received much attention because relatively high performance is achieved with low costs. For better programmability without much performance loss, several distributed shared memory (DSM) systems using relaxed memory consistency models and multiple writer protocols are intensively investigated, but there is no comparison between different DSM systems on the same environment. The user level software based DSM, TreadMarks and Adsmith are evaluated on a cluster of SUN workstations connected with a Ethernet. Performance results show TreadMarks and Adsmith achieve a comparable performance to PVM. It was revealed that Adsmith has better performance than TreadMarks because of its smaller coherency unit, although it requires more responsibilities for a programmer in data coherency maintenance. From the viewpoint of easy programming, TreadMarks lightens a programmer's load more than Adsmith.