Abstract

. We present an N-process algorithm for mutual exclusion under read/write atomicity that has O(1) time complexity in the absence of contention and \Theta(log N) time complexity under contention, where "time" is measured by counting remote memory references. This is the first such algorithm to achieve these time complexity bounds. Our algorithm is obtained by combining a new "fast-path" mechanism with an arbitration-tree algorithm presented previously by Yang and Anderson. 1 Introduction Recent work on mutual exclusion [3] has focused on the design of "scalable" algorithms that minimize the impact of the processor-to-memory bottleneck through the use of local spinning . A mutual exclusion algorithm is scalable if its performance degrades only slightly as the number of contending processes increases. In local-spin mutual exclusion algorithms, good scalability is achieved by requiring all busy-waiting loops to be read-only loops in which only locally-accessible shared variables ar...

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