The PVM 3.4 tracing facility and XPVM 1.1

One problem in developing a parallel program is monitoring its behavior for debugging and performance tuning. This paper discusses an enhanced tracing facility and tool for PVM (Parallel Virtual Machine), a message passing library for parallel processing in a heterogeneous environment. PVM supports mixed collections of workstation clusters, shared-memory multiprocessors, and massively parallel processors. The upcoming release of PVM, Version 3.4, contains a new, improved tracing facility which provides flexible, efficient access to run-time program information. This new tracing system supports a buffering mechanism to reduce perturbation of user applications caused by tracing, and a more flexible trace event definition scheme based on a self-defining data format. The new scheme expedites collection of program execution histories and allows for integration of user-defined custom trace events. Tracing instrumentation is built into the PVM library and allows on-the-fly adjustments to each task`s trace event mask, for control over the level of tracing detail. The graphical console and monitor XPVM have also been updated for better access to the new tracing functionality. Several new views have been implemented to utilize the additional tracing information now possible, including user-defined events. XPVM system has also been optimized for better real-time monitoring