 
Summary: Distributed Computing manuscript No.
(will be inserted by the editor)
Adaptive and Efficient Mutual Exclusion ?
Hagit Attiya and Vita Bortnikov
Department of Computer Science Technion, Haifa 32000, ISRAEL. hagit@cs.technion.ac.il, vita@versedge.com.
Summary. This paper presents adaptive algorithms for
mutual exclusion using only read and write operations;
the performance of the algorithms depends only on the
point contention, i.e., the number of processes that are
concurrently active during the algorithm execution (and
not on n, the total number of processes).
Our algorithm has O(k) remote step complexity and
O(log k) system response time, where k is the point con
tention. The remote step complexity is the maximalnum
ber of steps performed by a process where a wait is
counted as one step. The system response time is the
time interval between subsequent entries to the critical
section, where one time unit is the minimal interval in
which every active process performs at least one step.
The space complexity of this algorithm is O(N log n),
