Algorithms for search trees on message passing architectures

In this paper we describe a new algorithm for maintaining a balanced search tree on a message-passing MIMD architecture; the algorithm is particularly well suited for implementation on a small number of processors. We introduce a (2/sup B-2/, 2/sup B/) search tree that uses a bidirectional ring of O(log n) processors to store n entries. Update operations use a bottom-up node-splitting scheme, which performs significantly better than top-down search tree algorithms. The bottom-up algorithm requires many fewer messages and results in less blocking due to synchronization than top-down algorithms. Additionally, for a given cost ratio of computation to communication the value of B may be varied to maximize performance. Implementations on a parallel-architecture simulator are described.