The Dual Timestamping Methodology for Visualizing Distributed Applications

This article motivates and describes the dual timestamping methodology, a novel monitoring technique whose goal is to provide first class support for the visualization and animation of distributed and parallel applications. Central to this methodology is the use of both a primary and secondary timestamp in trace events. The primary timestamp is a logical timestamp that provides information about the concurrency of events. This information is useful for generating visualizations that depict the events as occurring in parallel. The secondary timestamp provides a normalized, causality preserving, real-time clock for use in performance visualization. The dual timestamping methodology is the basis for PVaniM, a collection of general purpose and application-specific visualizations of PVM applications. The implementation of PVaniM relies solely on macros and postprocessors. Because system modifications were not required, the PVaniM implementation strategies are general and easily adaptable to other distributed computing system domains