A token-based distributed group mutual exclusion algorithm with quorums

The group mutual exclusion problem is a generalization of mutual exclusion problem such that a set of processes in the same group can enter a critical section simultaneously. In this paper, we propose a distributed algorithm for the group mutual exclusion problem in asynchronous message passing distributed systems. Our algorithm is based on tokens, and a process that obtains a token can enter a critical section. To reduce message complexity, it uses a coterie as a communication structure when a process sends a request messages. Informally, a coterie is a set of quorums, each of which is a subset of the process set, and any two quorums share at least one process. The message complexity of our algorithm is O(vertical bar Q vertical bar) in the worst case, where vertical bar Q vertical bar is a quorum size that the algorithm adopts. Performance of the proposed algorithm is presented by analysis and discrete event simulation. In particular, the proposed algorithm achieves high concurrency, which is a performance measure for the number of processes that can be in a critical section simultaneously.