From Runtime Verification to Runtime Intervention and Adaptation

Abstract

Runtime verification monitors the execution of a program to determine if it satisfies (typically specified) correctness properties. But what happens when the program violates the correctness properties? The standard view is that continued execution may be unsafe, so the execution must be terminated. We present a variety of intervention techniques that enable software systems to exhibit remarkable flexibility and resilience in the face of errors and faults. These techniques can deliver safe continued execution that offers significant benefits over termination. We also present techniques that build on this malleability to purposefully modify the computation to adapt to changing needs, delivering benefits such as improved performance and reduced power consumption. These results place the advantages of runtime intervention and adaptation clearly on display. They also point the way to a future in which developers produce not the final version of the program which the system blindly executes, but instead a starting point for further modification and evolution as the system adapts to dynamically observed events and conditions.