Summary: Timing­based Mutual Exclusion with Local Spinning #
Yong­Jik Kim and James H. Anderson
Department of Computer Science
University of North Carolina at Chapel Hill
Chapel Hill, NC 27599­3175
Email: {kimy,anderson}@cs.unc.edu
July 2003
Abstract
We consider the time complexity of shared­memory mutual exclusion algorithms based on reads, writes,
and comparison primitives under the remote­memory­reference (RMR) time measure. For asynchronous
systems, a lower bound of #(log N/ log log N) RMRs per critical­section entry has been established in
previous work, where N is the number of processes. Also, algorithms with O(log N) time complexity
are known. Thus, for algorithms in this class, logarithmic or near­logarithmic RMR time complexity is
fundamentally required.
In this paper, we show that lower RMR time complexity is attainable in semi­synchronous systems
with delay statements. When assessing the time complexity of delay­based algorithms, the question of
whether delays should be counted arises. We consider both possibilities. Also of relevance is whether
delay durations are upper­bounded. Again, we consider both possibilities. For each of these possibilities,
we present an algorithm with either #(1) or #(log log N) time complexity. For the cases in which a
#(log log N) algorithm is given, we establish matching #(log log N) lower bounds. It follows from these

Source: Anderson, James - Department of Computer Science, University of North Carolina at Chapel Hill

Collections: Computer Technologies and Information Sciences