The Contention-Friendly Tree

This paper proposes a new lock-based concurrent binary tree using a methodology for writing concurrent data structures. This methodology limits the high contention induced by today’s multicore environments to come up with efficient alternatives to the most widely used search structures. Data structures are generally constrained to guarantee a big-oh step complexity even in the presence of concurrency. By contrast our methodology guarantees the big-oh complexity only in the absence of contention and limits the contention when concurrency appears. The key concept lies in dividing update operations within an eager abstract access that returns rapidly for efficiency reason and a lazy structural adaptation that may be postponed to diminish contention. Our evaluation clearly shows that our lock-based tree is up to 2.2× faster than the most recent lock-based tree algorithm we are aware of.