Can lock-free and combining techniques co-exist? A novel approach on concurrent queue

Concurrent queues are one of the most fundamental concurrent data structures. Most previous research focuses on how to avoid the contended hot spots, Head and Tail, and there are two contradictory approaches: (1) lock-free techniques [1], [2], which increase the degree of parallelism to improve performance and (2) combining techniques [3], where a single combining thread performs a batch operation for the pending requests from other threads to reduce synchronization cost in a high degree of parallelism.