Enabling a PC Cluster for High Performance Computing

Due to their excellent cost/performance ratio, clusters of PCs can be attractive high performance computing (HPC) platforms. Yet, their limited communication performance over standard LANs is still prohibitive for parallel applications. The SMiLE project (Shared Memory in a LAN-like Environment) at LRR-TUM adopts SCI interconnect technology (Scalable Coherent Interface) to build, and provide software for, a PC cluster which, with hardware-based distributed shared memory (DSM) and high performance communication characteristics, is regarded as well suited for HPC. The paper describes the key features of the enabling technology, SCI. It then discusses the developments and important results of the SMiLE project so far: the development and initial performance of a PCI/SCI interface card, and the design and initial performance results of low-latency communication layers, Active Messages and a sockets emulation library.