Formulating SoC test scheduling as a network transportation problem

A formulation of core-based system-on-chip (SoC) test scheduling as a network transportation problem is presented. Given a set of tests, with demands for transportation of test bits (either for test stimuli or test response) and unrelated parallel test resources (e.g., test access mechanisms or built-in self-test engines), the authors determine the start times and resource mappings of all the tests such that the finish time for the complete SoC test is minimized. The problem is NP-hard and they present an approximation algorithm using a result from the solution of the single source unsplittable flow problem. The proposed method uses the number of test bits that need to be transported for a test as the invariant and is hence relatively independent of the test application and execution model. Experimental results on benchmark SoCs demonstrate that their method outperforms the state-of-the-art integer linear programming formulations, not only in terms of schedule quality, but also significantly reduces the computation time.