An Ω (n log n) lower bound on the cost of mutual exclusion

Rui Fan, Nancy Lynch
2006 Proceedings of the twenty-fifth annual ACM symposium on Principles of distributed computing - PODC '06  
We prove an Ω(n log n) lower bound on the number of non-busywaiting memory accesses by any deterministic algorithm solving n process mutual exclusion that communicates via shared registers. The cost of the algorithm is measured in the state change cost model, a variation of the cache coherent model. Our bound is tight in this model. We introduce a novel information theoretic proof technique. We first establish a lower bound on the information needed by processes to solve mutual exclusion. Then
more » ... al exclusion. Then we relate the amount of information processes can acquire through shared memory accesses to the cost they incur. We believe our proof technique is flexible and intuitive, and may be applied to a variety of other problems and system models.
doi:10.1145/1146381.1146423 dblp:conf/podc/FanL06 fatcat:ikg3xqwhg5celgjcebj5qy3pui