Visual programming for message-passing systems

The attractiveness of visual programming stems in large part from the direct interaction with program elements as if they were real objects, since people deal better with concrete objects than with the abstract. This paper describes a new graph based software visualization tool for parallel message-passing programming named Visper that combines the levels of abstraction at which message-passing parallel programs are expressed and makes use of compositional programming. Central to the tool is the Process Communication Graph that correlates both the control and data flow graphs into a single graph formalism, without a need for complex textual annotation. The graph can express static and runtime communication and replication structures, as found in Message Passing Interface (MPI) and Parallel Virtual Machine (PVM). It also forms the basis for visualizing parallel debugging and performance.