A survey of concurrent priority queue algorithms

Algorithms for concurrent data structures have gained attention in recent years as multi-core processors have become ubiquitous. Using the example of a concurrent priority queue, this paper investigates different synchronization methods and concurrent algorithms. It covers traditional lock-based approaches, non-blocking algorithms as well as a method based on software transactional memory. Besides discussing correctness criteria for the various approaches, we also present performance results for all algorithms for various scenarios. Somewhat surprisingly, we find that a simple lock-based approach performs reasonable well, even though it does not scale with the number of threads. Better scalability is achieved by non-blocking approaches.