Abstract
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.