A perturbation-free replay platform for cross-optimized multithreaded applications

Abstract

Development of multithreaded applications is particularly tricky because of their non-deterministic execution behaviors. Tools that support the debugging and performance timing of such applications are needed. Key to the construction of such tools is the ability to repeat the nondeterministic execution behavior of a multithreaded application. A clean separation between the application and the system that runs it facilitates supporting that ability. This paper presents a platform for constructing such tools in a context in which any separation between the application and the underlying system (and between both and the platform's own instrumentation code) has been obscured. DejaVu supports deterministic replay of nondeterministic executions of multithreaded Java programs on the Jalapeno virtual machine (running on a uniprocessor). Jalapeno is written in Java and its optimizing compiler regularly integrates application, virtual machine, and DejaVu instrumentation code into unified machine-code sequences. DejaVu ensures deterministic replay through symmetric instrumentation-side-effect identical instrumentation in both record and replay modes-and remote reflection which exposes the state of an application without perturbing it.