On the Existence of Probe Effect in Multi-threaded Embedded Programs

Software instrumentation has been a convenient and portable approach for dynamic analysis, debugging, or profiling of program execution. Unfortunately, instrumentation may change the temporal behavior of multi-threaded program execution and result in different ordering of thread operations, which is called probe effect. While the approaches to reduce instrumentation overhead, to enable reproducible execution, and to enforce deterministic threading have been studied, no research has yet answered if an instrumented execution has the same behavior as the program execution without any instrumentation and how the execution gets changed if there were any. In this paper, we propose a simulation-based analysis to detect the changes of execution event ordering that are induced by instrumentation operations. The execution model of a program is constructed from the trace of instrumented program execution and is used in a simulation analysis where instrumentation overhead is removed. As a consequence, we can infer the ordering of events in the original program execution and verify the existence of probe effect resulted from instrumentation.