Concurrent Rebalancing on HyperRed-Black Trees
Joaquim Gabarró, Xavier Messeguer, Daniel Riu
Proceedings of the 17th International Conference of the Chilean Computer Science Society, pp. 93-104, IEEE Computer Society Press, 1997.

The HyperRed-Black trees are a relaxed version of Red-Black trees accepting high degree of concurrency. In the Red-Black trees consecutive red nodes are forbidden. This restriction has been withdrawn in the Chromatic trees. They have been introduced by O. Nurmi and E. Soisalon-Soininen to work in a concurrent environment. A Chromatic tree can have big clusters of red nodes surrounded by black nodes. Nevertheless, concurrent rebalancing of Chromatic trees into Red-Black trees has a serious drawback: in big cluster of red nodes only the top node can be updated. Direct updating inside the cluster is forbidden. This approach gives us limited degree of concurrency. The HyperRed-Black trees has been designed to solve this problem. It is possible to update red nodes in the inside of a red cluster. In a HyperRed-Black tree nodes can have a multiplicity of colors; they can be red, black or hyper-red.


Last modified: August 13, 1998.
Kim Skak Larsen (kslarsen@imada.sdu.dk)