Live Webcast 15th Annual Charm++ Workshop

The communication latency is a major issue that must be dealt with in parallel computing. The parallel computation model therefore must provide the ability to tolerate such latencies. Communication using blocking receives is the commonly used mechanism in parallel programming today. Message driven execution is an alternate mechanism which does not use receive style statements at all. The message driven execution style promotes the overlap of computation and communication: Programs written in this style exhibit increased latency tolerance. However, they are often difficult to develop and debug. We present a coordination language called Dagger to alleviate this problem. The language has a mechanism which is called - expect, that replaces the receive statement. It has been implemented in the Charm parallel programming system, and runs programs portably on a variety of parallel machines.