Is the Price of Anarchy the Right Measure for Load-Balancing Games?

International audiencePrice of Anarchy is an oft-used worst-case measure of the inefficiency of non-cooperative decentralized architectures. For a non-cooperative load-balancing game with two classes of servers and for a finite or infinite number of dispatchers, we show that the Price of Anarchy is an overly pessimistic measure that does not reflect the performance obtained in most instances of the problem. We explicitly characterize the worst-case traffic conditions for the efficiency of non-cooperative load-balancing schemes, and show that, contrary to a common belief, the worst inefficiency is in general not achieved in heavy-traffic