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Real-Time Systems

, Volume 52, Issue 6, pp 833–838 | Cite as

Federated scheduling admits no constant speedup factors for constrained-deadline DAG task systems

  • Jian-Jia ChenEmail author
Article

Abstract

In the federated scheduling approaches in multiprocessor systems, a task either (1) is restricted to execute sequentially on a single processor or (2) has exclusive access to the assigned processors. There have been several positive results to conduct good federated scheduling policies, which have constant speedup factors with respect to any optimal federated scheduling algorithm. This paper answers an open question: “For constrained-deadline task systems with directed acyclic graph (DAG) dependency structures, do federated scheduling policies have a constant speedup factor with respect to any optimal scheduling algorithm?” The answer is “No!” This paper presents an example, which demonstrates that any federated scheduling algorithm has a speedup factor of at least \(\Omega \,(\min \{M, N\})\) with respect to any optimal scheduling algorithm, where N is the number of tasks and M is the number of processors.

Keywords

Federated scheduling Speedup factors Multiprocessor scheduling 

Notes

Acknowledgments

This paper has been supported by DFG, as part of the Collaborative Research Center SFB876.

References

  1. Baruah S (2015a) The federated scheduling of constrained-deadline sporadic DAG task systems. In: Proceedings of the design, automation and test in Europe conference and exhibition, pp 1323–1328Google Scholar
  2. Baruah S (2015b) Federated scheduling of sporadic DAG task systems. In IEEE international parallel and distributed processing symposium, IPDPS, pp 179–186Google Scholar
  3. Baruah S (2015c) The federated scheduling of systems of conditional sporadic DAG tasks. In: Proceedings of the 15th international conference on embedded software (EMSOFT)Google Scholar
  4. Baruah SK, Mok AK, Rosier LE (1990) Preemptively scheduling hard-real-time sporadic tasks on one processor. In: IEEE real-time systems symposium, pp 182–190Google Scholar
  5. Chen JJ, Chakraborty S (2011) Resource augmentation bounds for approximate demand bound functions. In: IEEE real-time systems symposium, pp 272–281Google Scholar
  6. Li J, Chen J, Agrawal K, Lu C, Gill CD, Saifullah A (2014) Analysis of federated and global scheduling for parallel real-time tasks. In: 26th euromicro conference on real-time systems, ECRTS, pp 85–96Google Scholar

Copyright information

© Springer Science+Business Media New York 2016

Authors and Affiliations

  1. 1.Department of InformaticsTU Dortmund UniversityDortmundGermany

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