 
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
