Techniques for debugging parallel programs with flowback analysis

Flowback analysis is a powerful technique for debugging programs. It allows the programmer to examine dynamic dependences in a program's execution history without having to reexecute the program. The goal is to present to the programmer a graphical view of the dynamic program dependences. The authors are building a system, called PPD, that performs flowback analysis while keeping the execution time overhead low. They also extend the semantics of flowback analysis to parallel programs. This paper describes details of the graphs and algorithms needed to implement efficient flowback analysis for parallel programs. Execution-time overhead is kept low by recording only a small amount of trace during a program's execution.