Low Latency Message Passing on Workstation Clusters Using SCRAMNet

: Clusters of workstations are emerging as a popular platform for parallel and distributed computing. The performance of clusters of workstations depends greatly on the networks interconnecting them. In recent years many high performance interconnects have been developed. These interconnects provide high bandwidth. However, they also tend to have high communication latency. There is considerable ongoing research for providing message passing for clusters of workstations with low communication latency. SCRAMNet is an extremely low latency replicated non-coherent shared memory network. So far, this interconnect has been used only for real-time applications and very little work has been done to adapt it for use in cluster computing. This paper reports our early experiences with using SCRAMNet for cluster computing. The basic features of SCRAMNet are presented. We have implemented a user-level zero-copy message passing protocol called the BillBoard Protocol (BBP). This protocol and its AP..

Low-Latency Message Passing on Workstation Clusters using SCRAMNet

Clusters of workstations have emerged as a popular platform for parallel and distributed computing. Commodity high speed networks which are used to connect workstation clusters provide high bandwidth, but also have high latency. SCRAMNet is an extremely low latency replicated non-coherent shared memory network, so far used only for real-time applications. This paper reports our early experiences with using SCRAMNet for cluster computing. We have implemented a user-level zero-copy message passing protocol for SCRAMNet called the BillBoard Protocol (BBP). The one way latency for sending a 4-byte message between two nodes using the BBP is measured to be as low as 7.8 s. Since SCRAMNet supports hardware level replication of messages, it is possible to implement multicast with almost the same latency as point-to-point communication. Using the BBP, the latency for broadcasting short messages to 4 nodes is measured to be 10.1 s and the latency for a 4-node barrier is measured to be 37 s. W..