Live Webcast 15th Annual Charm++ Workshop

One of the simplest parallel programming paradigm is "master-slave". The main computation (the master) generates many subproblems, which are fired off to be executed by "someone else" (slave). The only interaction between the master and slave computations is that the master starts the slave computation, and the slave computation returns the result to the master. There are no significant dependencies among the slave computations. Although the parallel paradigm is simple, you still have to write a lot of code to use this paradigm on, say, a cluster of workstations. We have developed a library that simplifies development of master-slave applications.

The library is available as a part of the Charm distribution. It provides a call, to be used by the master, for firing off a subproblem with desired parameters, and another call that allows the master to wait for the results of the fired computations. You can either wait in a blocking mode for a specific result, or wait for "any of the pending" results. The system provides automatic load balancing of the pending slave tasks among available processors and automates the communication between master and slaves.

Typical applications of this library include genetic algorithms, certain Monte Carlo techniques, simple cryptography style applications (or any application where a SETI-at-home type approach is feasible).