Improving PVM Performance Using ATOMIC User-Level Protocol

Parallel virtual machine (PVM) software system provides a programming environment that allows a collection of networked workstations to appear as a single concurrent computational resource. The performance of parallel applications in this environment depends on the performance of reliable data transfers between tasks. In this paper, we improve PVM communication performance over the ATOMIC LAN, a gigabit per-second local area network. This is achieved by separating the PVM data-transmission path from the PVM control-message path and transmitting PVM data messages over a user-level application programming interface (API) provided by the Myrinet ATOMIC interface. The Myrinet-API, although signiicantly faster than the TCP/IP kernel stack, does not provide reliable communication. Therefore, a user-level protocol has been developed based on the Myrinet-API to ooer reliable sequenced packet delivery. This protocol provides faster data transfers between PVM tasks over the ATOMIC LAN. Performance results obtained at USC/ISI demonstrate that our version of PVM can reach up to 140 Mbps throughput, which is 94% of the achievable network bandwidth over the ATOMIC LAN.