Specification, verification, and synthesis of concurrency control components

Abstract

Run-time errors in concurrent programs are generally due to the wrong usage of synchronization primitives such as monitors. Conventional validation techniques such as testing become ineffective for concurrent programs since the state space increases exponentially with the number of concurrent processes. In this paper, we propose an approach in which 1) the concurrency control component of a concurrent program is formally specified, 2) it is verified automatically using model checking, and 3) the code for concurrency control component is automatically generated. We use monitors as the synchronization primitive to control access to a shared resource by multipleconcurrent processes. Since our approach decouples the concurrency control component from the rest of the implementation it is scalable. We demonstrate the usefulness of our approach by applying it to a case study on Airport Ground Traffic Control.We use the Action Language to specify the concurrency control component of a system. Action Language is a specification language for reactive software systems. It is supported by an infinite-state model checker that can verify systems with boolean, enumerated and udbounded integer variables. Our code generation tool automatically translates the verified Action Language specification into a Java monitor. Our translation algorithm employs symbolic manipulation techniques and the specific notification pattern to generate an optimized monitor class by eliminating the context switch overhead introduced as a result of unnecessary thread notification. Using counting abstraction, we show that we can automatically verify the monitor specifications for arbitrary number of threads.