6,263 research outputs found
Effective lock handling in stateless model checking.
Stateless Model Checking (SMC) is a verification technique for concurrent programs that checks for safety violations by exploring all possible thread interleavings. SMC is usually coupled with Partial Order Reduction (POR), which exploits the independence of instructions to avoid redundant explorations when an equivalent one has already been considered. While effective POR techniques have been developed for many different memory models, they are only able to exploit independence at the instruction level, which makes them unsuitable for programs with coarse-grained synchronization mechanisms such as locks. We present a lock-aware POR algorithm, LAPOR, that exploits independence at both instruction and critical section levels. This enables LAPOR to explore exponentially fewer interleavings than the state-of-the-art techniques for programs that use locks conservatively. Our algorithm is sound, complete, and optimal, and can be used for verifying programs under several different memory models. We implement LAPOR in a tool and show that it can be exponentially faster than the state-of-the-art model checkers
Thread-Modular Static Analysis for Relaxed Memory Models
We propose a memory-model-aware static program analysis method for accurately
analyzing the behavior of concurrent software running on processors with weak
consistency models such as x86-TSO, SPARC-PSO, and SPARC-RMO. At the center of
our method is a unified framework for deciding the feasibility of inter-thread
interferences to avoid propagating spurious data flows during static analysis
and thus boost the performance of the static analyzer. We formulate the
checking of interference feasibility as a set of Datalog rules which are both
efficiently solvable and general enough to capture a range of hardware-level
memory models. Compared to existing techniques, our method can significantly
reduce the number of bogus alarms as well as unsound proofs. We implemented the
method and evaluated it on a large set of multithreaded C programs. Our
experiments showthe method significantly outperforms state-of-the-art
techniques in terms of accuracy with only moderate run-time overhead.Comment: revised version of the ESEC/FSE 2017 pape
Event Stream Processing with Multiple Threads
Current runtime verification tools seldom make use of multi-threading to
speed up the evaluation of a property on a large event trace. In this paper, we
present an extension to the BeepBeep 3 event stream engine that allows the use
of multiple threads during the evaluation of a query. Various parallelization
strategies are presented and described on simple examples. The implementation
of these strategies is then evaluated empirically on a sample of problems.
Compared to the previous, single-threaded version of the BeepBeep engine, the
allocation of just a few threads to specific portions of a query provides
dramatic improvement in terms of running time
- …