IJPP manuscript No. (will be inserted by the editor) Using Discrete Event Simulation to Analyze Contention Managers

Abstract Understanding the behavior and benefits of contention managers is impor-tant for designing transactional memory implementations. Contention manager de-sign is closely tied to other design decisions in a transaction memory implementation, and therefore experiments to compare the behaviors of contention managers are diffi-cult. This paper presents a discrete event simulator that allows researchers to explore the behavior of contention managers and even to perform experiments that compare lazy conflict detection without contention management to eager detection combined with a contention manager. For our benchmarks, we found that lazy conflict detec-tion was competitive with the best contention managers. Our experiments confirm that contention management design is critical for transactional memories that use ea-ger validation. We used the simulator to explore new tiered contention managers that combine livelock-prone contention managers with livelock-free contention managers to provide the benefits of the livelock-prone contention manager while avoiding its pathological behaviors under contention