Lock-Free Binary Search Tree Based on Leaf Search

Binary search tree is one of the most important data structures in program design. This article proposes a novel lock-free algorithm, which can implement the lock-free operations, such as search, insert and delete, using compare and swap (CAS). Unlike the previous studies of handling the inside node in a tree, the authors' algorithm handles the insert and delete operations by considering of the subtree. This article presents the details of the lock-free algorithm, which can effectively reduce the contention between the update operations. The experiment compares the algorithm with other two lock-free algorithms by throughput. Evaluation results show that the throughput of the algorithm outperforms that of the other two concurrent BSTs when the number of threads is more than 4. The authors' algorithm will be competitive when the concurrency is high.