Supporting small accesses for the parallel file subsystem on distributed shared memory systems

The main goal of parallel file subsystem on Distributed Shared Memory (DSM) systems is to reduce the network traffic in page based software DSM systems, thereby improving system performance. Our laboratory has built a prototype of the parallel file subsystem on two DSM systems, namely Cohesion and TreadMarks. But these two prototypes have several limitations: users must read/write the whole parallel file in a single access; users cannot modify an existing parallel file; the parallel file request must be issued from the root node. In our new parallel file subsystem on Teamster, a new DSM system developed by our laboratory, we eliminate the limitations revealed in the two previous parallel file subsystems. In addition, we have developed two new mechanisms, the software cache mechanism and the asynchronous file offset mechanism, to lessen the performance degradation caused by the frequent small accesses.