Path-aware Time-triggered Runtime Verification

Time-triggered runtime verification aims at establishing a framework that provides bounded overhead and predictable behavior at run time. A time-triggered monitor runs in parallel with the program under inspection and periodically samples the program state to evaluate a set of properties. However, a time-triggered monitor working with a fixed sampling frequency often suffers from redundant sampling, which results in excessive overhead. In this paper, we propose an effective approach to reduce redundant sampling. Our approach calculates the sampling frequency with respect to the program behavior at run time. We further advance this approach to dynamically adjust the sampling frequency at run time by predicting the program behavior using symbolic execution. Our approach is fully implemented in a tool chain. Experiments on the SNU benchmark suit show that our approach reduces the sampling frequency, runtime overhead, and the number of redundant samples by up to 3.5 times, 69%, and 86%, respectively.