Understanding complex multithreaded software systems by using trace visualization

Abstract

Understanding multithreaded software systems is typically a tedious task: Due to parallel execution and interactions between multiple threads, such a system's runtime behavior is often much more complex than the behavior of a single-threaded system. For many maintenance activities, system understanding is a prerequisite. Hence, tasks such as bug fixing or performance optimization are highly demanding in the case of multithreaded systems. Unfortunately, state-of-the-art tools for system understanding and debuggers provide only limited support for these systems. We present a dynamic analysis and visualization technique that helps developers in understanding multithreaded software systems in general and in identifying performance bottlenecks in particular. The technique first performs method boundary tracing. Second, developers perform a post-mortem analysis of a system's behavior using visualization optimized for trace data of multithreaded software systems. The technique enables developers to understand how multiple threads collaborate at runtime. The technique is integrated into a professional and scalable tool for visualizing the behavior of complex software systems. In case studies, we have tested the technique with industrially developed, multithreaded software systems to understand system behavior and to identify multithreading-related performance bottlenecks.