High Performance Commodity Network Interfaces

As commodity workstations become faster with increases in processor technology, the need for higher performance network interfaces becomes more pressing. While current commodity network interface cards provide ample bandwidth for bulk data transfers, the latency imposed on small messages can be large. However, to attempt to harness the potential compute power of a cluster of workstations at commodity prices, attention must be paid to the way in which the nodes are interconnected. The high latency incurred by standard protocol stacks on commodity hardware makes clusters of workstations appropriate only for problems that exhibit extremely high computation to communication ratios. Projects such as GAMMA from the University of Genoa 8] have shown that by reducing the operating system overhead, the latency associated with communications can be signiicantly reduced, even on commodity hardware. Other projects, such as Myricom's Myrinet 6], and DEC/Compaq's Memory Channel 14], show that a different network interface architecture can also yield significant performance gains. By taking advantage of modern, high performance, highly integrated microcontrollers, future network card designs could realize even higher performance through lower operating system overhead and more capable network interfaces. 1 Introduction In recent years, the interest in achieving high performance computing on networks of workstations 2] has grown, as the power of commodity processors has increased. Even though processors continue to increase in performance as predicted by Moore's Law, the price of machines has dropped, making the cost-eeectiveness of cluster computing, as measured in compute performance per dollar spent, increase even faster. However, to exploit the high performance potential of modern processors, it is necessary to nd a way to interconnect the processing elements so that they may communicate ef-ciently to work together on large problems. In a custom designed highly parallel computer, a signiicant portion of time and resources goes into the design of the interconnec