Xab : A Tool for Monitoring PVM Programs 1

Xab (X-window Analysis and deBugging) is a tool for run time monitoring of PVM (Parallel Virtual Machine) programs. PVM supports the programming of a network of heterogeneous computers as a single parallel computer. Using Xab, PVM programs can easily be instrumented and monitored. Xab uses PVM to monitor PVM programs. This makes Xab very portable but it leads to interesting issues of how to make Xab peacefully coincide with the programs it monitors. Xab consists of three main components, a user library, a monitoring program, and an X windows front end. The user library provides instrumented versions of the PVM calls. The monitoring program runs as a PVM process and gathers monitor events in the form of PVM messages. The Xab front end displays information graphically about PVM processes and messages. This paper discusses the design, implementation, and use of the Xab tool. Related work is brie y presented and contrasted with the approach taken with Xab. How Xab works and how it is used are discussed in detail. Finally, the current status of Xab is presented along with future directions of where the research may go from here.