Summary: Nonatomic Mutual Exclusion with Local Spinning #
Tmax Soft Research Center
2726 Seohyeondong, Seongnamsi
Gyeonggido, Korea 463824
James H. Anderson
Department of Computer Science
University of North Carolina at Chapel Hill
Chapel Hill, NC 275993175
April 2003, Revised October 2005
We present an Nprocess localspin mutual exclusion algorithm, based on nonatomic reads and writes,
in which each process performs #(log N) remote memory references to enter and exit its critical section.
This algorithm is derived from Yang and Anderson's atomic treebased localspin algorithm in a way
that preserves its time complexity. No atomic read/write algorithm with better asymptotic worstcase
time complexity (under the remotememoryreferences measure) is currently known. This suggests that
atomic memory is not fundamentally required if one is interested in worstcase time complexity.
The same cannot be said if one is interested in fastpath algorithms (in which contentionfree time