On maximizing the throughput of multiprocessor tasks

  • Authors:
  • Aleksei V. Fishkin;Guochuan Zhang

  • Affiliations:
  • Institut für Informatik und Praktische Mathematik, Universität Kiel, Olshausenstrasse 40, 24098 Kiel, Germany;Institut für Informatik und Praktische Mathematik, Universität Kiel, Olshausenstrasse 40, 24098 Kiel, Germany

  • Venue:
  • Theoretical Computer Science
  • Year:
  • 2003

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Abstract

We consider the problem of scheduling n independent multiprocessor tasks with due dates and unit processing times, where the objective is to compute a schedule maximizing the throughput. We derive the complexity results and present several approximation algorithms. For the parallel variant of the problem, we introduce the first-fit increasing algorithm and the latest-fit increasing algorithm, and prove that their worst-case ratios are 2 and 2 - 1/m, respectively (m ≥ 2 is the number of processors). Then we propose a revised algorithm with a worst-case ratio bounded by 3/2- 1/(2m) (m is odd) and 3/2-1/(2m-2) (m is even). For the dedicated variant, we present a simple greedy algorithm. We show that its worst-case ratio is bounded by √m + 1. We straighten this result by showing that the problem cannot be approximated within a factor of m1/2-ε for any ε 0, unless NP = ZPP.