Methods to improve reverse debugging performance

Abstract

Reverse debugging is software development technique that effectively helps to fix bugs caused by nondeterministic program behavior. It allows inspecting past program’s state without rerun. The paper describes implementation of software reverse debugging using deterministic replay based on the QEMU emulator. We present ways to improve debugging performance by reducing saved data, using copy-on-write snapshots’ format and indexing/compressing of replay log. QEMU supports a common user interface for reverse debugging in GDB debugger which allows using reverse-continue, reverse-nexti, reverse-stepi and reverse-finish commands. Time required for these commands’ execution depends on taking snapshots frequency in recording replay log. This paper also presents assessment of snapshots frequency for better performance.

Keywords

• обратная отладка
• детерминированное воспроизведение
• qemu
• симулятор