Fast and Scalable Group Mutual Exclusion

TL;DR

This paper introduces a highly efficient group mutual exclusion algorithm that achieves constant step and space complexity in asynchronous shared-memory systems, improving scalability and performance over existing solutions.

Contribution

The paper presents the first GME algorithm with O(1) step-complexity for concurrent entering and reduced space complexity, advancing the state of the art.

Findings

Achieves O(1) step-complexity in the absence of conflicting requests.

Uses O(1) space per GME object with sufficient objects.

Can be modified for bounded space variables.

Abstract

The group mutual exclusion (GME) problem is a generalization of the classical mutual exclusion problem in which every critical section is associated with a type or session. Critical sections belonging to the same session can execute concurrently, whereas critical sections belonging to different sessions must be executed serially. The well-known read-write mutual exclusion problem is a special case of the group mutual exclusion problem. In this work, we present a novel GME algorithm for an asynchronous shared-memory system that, in addition to satisfying lockout freedom, bounded exit and concurrent entering properties, has O(1) step-complexity when the system contains no conflicting requests as well as O(1) space-complexity per GME object when the system contains sufficient number of GME objects. To the best of our knowledge, no existing GME algorithm has O(1) step-complexity for concurrent entering. Moreover, most existing GME algorithms have {\Omega}(n) space complexity per GME object, where n denotes the number of processes in the system. We also show that our GME algorithm can be easily modified to use bounded space variables.