Randomized On-line Algorithms for the Page Replication Problem

In a distributed shared memory system, each read-only page needs to be located at appropriate processors by replication to make the total access cost lower. In this paper, on-line algorithms to implement this low-cost locating are considered in terms of competitiveness. Specifically, we first show that the application of algorithms based on randomized algorithms for the page migration problem to the page replication problem can beat the deterministic lower bound for tree networks. Coinflipping algorithms are also investigated in this paper. We prove that a coin-flipping algorithm is 2-competitive for trees. For circles we propose the first 4-competitive coin-flipping algorithm which may be generalized for general networks.