Dynamic Analysis of Embedded Software Using Execution Replay

For program optimization and debugging, dynamic analysis tools, e.g., profiler, data race detector, are widely used. To gather execution information, software instrumentation is often employed for its portability and convenience. Unfortunately, instrumentation overhead may change the execution of a program and lead to distorted analysis results, i.e., probe effect. In embedded software which usually consists of multiple threads and external inputs, program executions are determined by the timing of external inputs and the order of thread executions. Hence, probe effect incurred in an analysis of embedded software will be more prominent than in desktop software. This paper presents a reliable dynamic analysis method for embedded software using deterministic replay. The idea is to record thread executions and I/O with minimal record overhead and to apply dynamic analysis tools in replayed execution. For this end, we have developed a record/replay framework called P-Replayer, based on Lamport's happens-before relation. Our experimental results show that dynamic analyses can be managed in the replay execution enabled by P-Replayer as if there is no instrumentation on the program.