withO - the - Shelf RISC

Multithreaded architectures have been proposed for future multiprocessor systems due to their ability to cope with network and synchronization latencies. Some of these architectures depart signiicantly from current RISC processor designs, while others retain most of the RISC core unchanged. However, in light of the very low cost and excellent performance of oo-the-shelf microprocessors it seems important to determine whether it is possible to build eecient multithreaded machines based on unmodiied RISC processors, or if such an approach faces inherent limitations. This paper describes the costs and beneets of running multithreaded programs on the EARTH-MANNA system, which uses two Intel i860 XP microprocessors per node.