Summary: A Theory of Competitive Analysis for Distributed Algorithms
June 10, 2003
We introduce a theory of competitive analysis for distributed algorithms. The first steps
in this direction were made in the seminal papers of Bartal, Fiat, and Rabani , and of
Awerbuch, Kutten, and Peleg , in the context of data management and job scheduling.
In these papers, as well as in other subsequent work [4, 15, 19, 14], the cost of a distributed
algorithm is compared to the cost of an optimal global-control algorithm. (This is also done
implicitly in the earlier work of Awerbuch and Peleg .) Here we introduce a more refined
notion of competitiveness for distributed algorithms, one that reflects the performance of
distributed algorithms more accurately. In particular, our theory allows one to compare
the cost of a distributed on-line algorithm to the cost of an optimal distributed algorithm.
We demonstrate our method by studying the cooperative collect primitive, first ab-
stracted by Saks, Shavit, and Woll . We present two algorithms (with different strengths)
for this primitive, and provide a competitive analysis for each one.