Perfectly balanced allocation

Document Type

Article

Publication Date

1-1-2003

Abstract

We investigate randomized processes underlying load balancing based on the multiple-choice paradigm: m balls have to be placed in n bins, and each ball can be placed into one out of 2 randomly selected bins. The aim is to distribute the balls as evenly as possible among the bins. Previously, it was known that a simple process that places the balls one by one in the least loaded bin can achieve a maximum load of m/n + θ(log log n) with high probability. Furthermore, it was known that it is possible to achieve (with high probability) a maximum load of at most ⌈m/n⌉ + 1 using maximum flow computations. In this paper, we extend these results in several aspects. First of all, we show that if m ≥ cn log n for some sufficiently large c, then a perfect distribution of balls among the bins can be achieved (i.e., the maximum load is ⌈m/n⌉) with high probability. The bound for m is essentially optimal, because it is known that if m ≤ c′ n log n for some sufficiently small constant c′, the best possible maximum load that can be achieved is ⌈m/n⌉ + 1 with high probability. Next, we analyze a simple, randomized load balancing process based on a local search paradigm. Our first result here is that this process always converges to a best possible load distribution. Then, we study the convergence speed of the process. We show that if m is sufficiently large compared to n, then no matter with which ball distribution the system starts, if the imbalance is Δ, then the process needs only Δ·nO(1) steps to reach a perfect distribution, with high probability. We also prove a similar result for m ≈ n, and show that if m = O(n log n/ log log n), then an optimal load distribution (which has the maximum load of ⌈m/n⌉ +1) is reached by the random process after a polynomial number of steps, with high probability. © Springer-Verlag Berlin Heidelberg 2003.

Identifier

35248849804 (Scopus)

ISBN

[3540407707, 9783540407706]

Publication Title

Lecture Notes in Computer Science Including Subseries Lecture Notes in Artificial Intelligence and Lecture Notes in Bioinformatics

External Full Text Location

https://doi.org/10.1007/978-3-540-45198-3_21

e-ISSN

16113349

ISSN

03029743

First Page

240

Last Page

251

Volume

2764

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