Reducing State Explosion for Software Model Checking with Relaxed Memory Consistency Models
This work addresses a critical scalability issue in verifying concurrent software under relaxed memory models, though it is incremental as it builds on existing model checking techniques.
The paper tackles the state explosion problem in software model checking under relaxed memory consistency models by providing optimizations and applying them to McSPIN, a model checker for such models, resulting in experimental verification of concurrent copying garbage collection protocols, which is a first in this context.
Software model checking suffers from the so-called state explosion problem, and relaxed memory consistency models even worsen this situation. What is worse, parameterizing model checking by memory consistency models, that is, to make the model checker as flexible as we can supply definitions of memory consistency models as an input, intensifies state explosion. This paper explores specific reasons for state explosion in model checking with multiple memory consistency models, provides some optimizations intended to mitigate the problem, and applies them to McSPIN, a model checker for memory consistency models that we are developing. The effects of the optimizations and the usefulness of McSPIN are demonstrated experimentally by verifying copying protocols of concurrent copying garbage collection algorithms. To the best of our knowledge, this is the first model checking of the concurrent copying protocols under relaxed memory consistency models.