Flexible Resource Allocation to Interval Jobs

Dmitriy Katz, Baruch Schieber, Hadas Shachnai

Research output: Contribution to journalArticlepeer-review

2 Scopus citations


Motivated by the cloud computing paradigm, and by key optimization problems in all-optical networks, we study two variants of the classic job interval scheduling problem, where a reusable resource is allocated to competing job intervals in a flexible manner. Each job, Ji, requires the use of up to rmax(i) units of the resource, with a profit of pi≥ 1 accrued for each allocated unit. The goal is to feasibly schedule a subset of the jobs so as to maximize the total profit. The resource can be allocated either in contiguous or non-contiguous blocks. These problems can be viewed as flexible variants of the well known storage allocation and bandwidth allocation problems. We show that the contiguous version is strongly NP-hard, already for instances where all jobs have the same profit and the same maximum resource requirement. For such instances, we derive the best possible positive result, namely, a polynomial time approximation scheme. We further show that the contiguous variant admits a (54+ε)-approximation algorithm, for any fixed ε> 0 , on instances whose job intervals form a proper interval graph. At the heart of the algorithm lies a non-standard parameterization of the approximation ratio itself, which is of independent interest. For the non-contiguous case, we uncover an interesting relation to the paging problem that leads to a simple O(nlog n) algorithm for uniform profit instances of n jobs. The algorithm is easy to implement and is thus practical.

Original languageEnglish (US)
Pages (from-to)3217-3244
Number of pages28
Issue number8
StatePublished - Aug 1 2019

All Science Journal Classification (ASJC) codes

  • General Computer Science
  • Computer Science Applications
  • Applied Mathematics


  • Approximation algorithms
  • Bandwidth allocation
  • Cloud computing
  • Elastic all-optical networks
  • Flexible storage allocation
  • Paging problem
  • Scheduling


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