Scheduling sequence selection for generating test data to cover paths of MPI programs

Abstract

Abstract Context: As one of key tasks in software testing, test data generation has been receiving widespread attention in recent years. Message-passing Interface (MPI) programs, which are one representative type of parallel programs, have the characteristic of non-determinism, which is reflected by the non-deterministic execution under different scheduling sequences against the same program input. Previous studies have shown that different difficulties are raised in generating test data under different scheduling sequences, suggesting that selecting appropriate scheduling sequences is beneficial to a high efficiency. Objective: We propose a method of selecting a superior and feasible scheduling sequence for generating test data in the criterion of path coverage against each target path of an MPI program. Method: In the proposed method, a number of program inputs are first sampled by Latin hypercube sampling. Then, the program is executed against each sample under each scheduling sequence, and all the scheduling sequences are sorted according to the similarities between the paths traversed by these samples and the target one. Finally, the feasibility of a scheduling sequence with the best quality is investigated based on the symbolic execution. Results: We apply the proposed method to seven typical MPI programs and compare it with the random one. The experimental results show that test data covering the target path can be generated under the selected scheduling sequence with high success rate and low time consumption. Conclusion: The proposed method takes the influence of scheduling sequences on generating test data into consideration, thus providing a competent way to test parallel programs.