Abstract. Managing and controlling interference conditions in multi-threaded programs has been an issue of worry for application developers for a long time. Typically, when write events from two concurrent threads to the same shared variable are not properly protected, an occurrence of the interference bug pattern could be exposed. We propose a mathematical formulation and its resolution to maximize the possibility of exposing occurrences of the interference bug pattern. We formulate and solve the issue as an optimization problem that gives us (1) the optimal position to inject a delay in the execution flow of a thread and (2) the optimal duration for this delay to align at least two different write events in a multi-threaded program. To run the injected threads and calculate the thread execution times for validating the results, we use a virtual platform modelling a perfectly parallel system. All the effects due to the operating system's scheduler or the latencies of hardware components are reduced to zero, exposing only the interactions between threads. To the best of our knowledge, no previous work has formalized the alignment of memory access events to expose occurrences of the interference bug pattern. We use three different algorithms (random, stochastic hill climbing, and simulated annealing) to solve the optimization problem and compare their performance. We carry out experiments on four small synthetic programs and three real-world applications with varying numbers of threads and read/write executions. Our results show that the possibility of exposing interference bug pattern can be significantly enhanced, and that metaheuristics (hill climbing and simulated annealing) provide much better results than a random algorithm.

Abstract-We present ACRE, an Automated aspeCt cREator, to use aspect-oriented programming (AOP) to perform memory, invariant and interferences testing for software programs written in C++. ACRE allows developers without knowledge in AOP to use aspects to test their programs without modifying the behavior of their source code. ACRE uses a domain-specific language (DSL), which statements testers insert into the source code like comments to describe the aspects to be used. The presence of DSL statements in the code does not modify the program's compilation and behavior. ACRE parses the DSL statements and automatically generates appropriate aspects that are then weaved into the source code to identify bugs due to memory leaks, incorrect algorithm implementation, or interference among threads. Thanks to the use of aspects and ACRE, testers can add or remove tests easily. Using an aspect generated by ACRE, we find a memory leak in a complex C++ software program, NOMAD, used in both industry and research. We also verify a crucial mathematical point of the algorithm behind NOMAD and collect data to find possible interference bugs, in NOMAD.