TPVM: distributed concurrent computing with lightweight processes

The TPVM (Threads-oriented PVM) system, is an experimental auxiliary subsystem for the PVM distributed system, which supports the use of lightweight processes or "threads" as the basic unit of parallelism and scheduling. TPVM provides a library interface which presents both a traditional, task based, explicit message passing model, as well as a data-driven scheduling model that enables straightforward specification of computation based on data dependencies. Our system design is still under development, but a prototype implementation has allowed us to perform a number of preliminary experiments. These have provided strong evidence that TPVM can offer improved performance, processor utilization, and load balance to several application categories. Through our experiments we have also determined that the current TPVM design is not very well suited to certain types of applications, most notably highly synchronous, SPMD-style algorithms.