Comparing the Performance of the PastSet Distributed Shared Memory System using TCP / IP and M-VIA

Using TCP/IP or M-VIA, the performance of the structured distributed shared memory system PastSet is measured and compared to a reference single-node implementation (excluding all intra-node communication). The latencies of PastSet-operations are measured using several micro-benchmarks. For the experiment setup used, M-VIA latencies are shown to be between 1.4 and 2.2 times lower than the comparable latencies using TCP/IP. For a data size of 31KB, this corresponds to a difference of more than one millisecond. Depending on the thread-allocation policy applied in the PastSet server, PastSet latencies using TCP/IP may exhibit increased variance compared to the corresponding latencies using M-VIA. The increased latency and variance may mask the performance characteristics of the PastSet system.