## Abstract

We revisit from a fairness point of view the problem of online load balancing in the restricted assignment model and the 1-∞ model. We consider both a job-centric and a machine-centric view of fairness, as proposed by Goel et al. [11]. These notions are equivalent to the approximate notion of prefix competitiveness proposed by Kleinberg, Rabani and Tardos [14], as well as to the notion of approximate majorization, and they generalize the well studied notion of max-min fairness. We resolve a question posed by Goel, Meyerson and Plotkin [11] proving that the greedy strategy is globally O(log m)-fair, where m denotes the number of machines. This result improves upon the analysis of [11] who showed that the greedy strategy is globally O(log n) -fair, where n is the number of jobs. Typically, n ≫ m, and therefore our improvement is significant. Our proof matches the known lower bound for the problem with respect to the measure of global fairness. The improved bound is obtained by analyzing, in a more accurate way, the more general restricted assignment model studied previously in [6]. We provide an alternative bound which is not worse than the bounds of [6], and it is strictly better in many cases. The bound we prove is, in fact, much more general and it bounds the load on any prefix of most loaded machines. As a corollary from this more general bound we get that the greedy algorithm results in an assignment that is globally O(log m)-balanced. The last result generalizes the previous result of [11] who proved that the greedy algorithm yields an assignment that is globally O(log m)-balanced for the 1-∞ model.

Original language | English |
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Title of host publication | SPAA 2006 |

Subtitle of host publication | 18th Annual ACM Symposium on Parallelism in Algorithms and Architectures |

Publisher | Association for Computing Machinery |

Pages | 291-298 |

Number of pages | 8 |

ISBN (Print) | 1595934529, 9781595934529 |

DOIs | |

State | Published - 2006 |

Externally published | Yes |

Event | SPAA 2006: 18th Annual ACM Symposium on Parallelism in Algorithms and Architectures - Cambridge, MA, United States Duration: 30 Jul 2006 → 2 Aug 2006 |

### Publication series

Name | Annual ACM Symposium on Parallelism in Algorithms and Architectures |
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Volume | 2006 |

### Conference

Conference | SPAA 2006: 18th Annual ACM Symposium on Parallelism in Algorithms and Architectures |
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Country/Territory | United States |

City | Cambridge, MA |

Period | 30/07/06 → 2/08/06 |

## Keywords

- Competitive analysis
- Greedy algorithm
- Load balancing
- Online algorithms
- Scheduling