Detection of high-level execution patterns in reactive behavior of control programs

Abstract

This paper presents an approach to extract high-level patterns from traces of programmable logic control (PLC) programs recorded with a deterministic replay debugging tool. Our deterministic replay debugging works by recording an application run in real-time with minimal overhead so that it can be reproduced afterwards. In a subsequent phase, the application is replayed in offline mode to produce a more detailed trace log with additional information about the application run. A software developer can replay the program in a debugger and use debugger features to analyze the program run and locate errors. However, due to the vast amount of data and the complex behavior of reactive control programs, a normal debugger is usually only a poor support in comprehending the program behavior. In this paper we present an approach to analyze recorded program runs of PLC applications. We present a technology to visualize the reactive behavior of a program run and find recurring high-level execution patterns in long-running applications. We give an overview of possible application scenarios to support program comprehension, testing, and debugging.