Exploiting transition locality in automatic verification of finite-state concurrent systems

Abstract

In this paper we show that statistical properties of the transition graph of a system to be verified can be exploited to improve memory or time performances of verification algorithms.\ud We show experimentally that protocols exhibit transition locality. That is, with respect to levels of a breadth-first state space exploration, state transitions tend to be between states belonging to close levels of the transition graph. We support our claim by measuring transition locality for the set of protocols included in the Murphi verifier distribution .\ud We present a cache-based verification algorithm that exploits transition locality to decrease memory usage and a disk-based verification algorithm that exploits transition locality to decrease disk read accesses, thus reducing the time overhead due to disk usage. Both algorithms have been implemented within the Murphi verifier.\ud Our experimental results show that our cache-based algorithm can typically save more than 40% of memory with an average time penalty of about 50% when using (Murphi) bit compression and 100% when using bit compression and hash compaction, whereas our disk-based verification algorithm is typically more than ten times faster than a previously proposed disk-based verification algorithm and, even when using 10% of the memory needed to complete verification, it is only between 40 and 530% (300% on average) slower than (RAM) Murphi with enough memory to complete the verification task at hand. Using just 300 MB of memory our disk-based Murphi was able to complete verification of a protocol with about 109 reachable states. This would require more than 5 GB of memory using standard Murphi

Formal Specification and Quantitative Analysis of a Constellation of Navigation Satellites

“…Moreover, the approach of system level formal verification to exploit a simulator in order to carry out formal verification has been further developed in [32,33] and applied to biological contexts. Finally, all these approaches use the explicit model checker CMurphi [34].…”

Model Checking Driven Simulation of Sat Procedures

“…Examples are SPIN [10] and CMurphi [2,3]. Since CMurphi has already the capability of handling finite precision (i.e., C-like) real numbers, as well as interfaces toward external functions (like the one implemented by the simulator) we decided to base our work on CMurphi.…”

“…We choose CMurphi [2,3] as the model checker suitable for the context of this paper. The model checker role is twofold.…”

Toward reliable and efficient message passing software through formal analysis

“…This protocol has more than 3 × 10 9 states, and its verification with standard Murphi would require a huge amount of RAM memory (assuming 40 bits for each state in hash compaction, we would need 15 GB of RAM for the hash table only), as well as an unacceptable computational time. On the other hand, by using a disk version of Murphi [32], the computation lasts more than 1 week (we do not know the exact amount of time, but a projection based on the first part of the verification leads to a probable execution time of 3 weeks). However, we successfully completed the verification of this protocol with Eddy Murphi on 60 nodes in approximately 9 hours.…”