Efficient online schedulability tests for real-time systems

Tei Wei Kuo*, Li-Pin Chang, Yu Hua Liu, Kwei Jay Lin

*Corresponding author for this work

Research output: Contribution to journalArticlepeer-review

30 Scopus citations


Many computer systems, such as those for open system environments or multimedia services, need an efficient schedulability test for online admission control of new jobs. Although various polynomial time schedulability tests have been proposed, they often fail to decide the schedulability of the system precisely when the system is heavily loaded. On the other hand, most precise schedulability tests proposed to date have a high complexity and may not be suitable for online tests. In this paper, we present new efficient online schedulability tests for both the periodic process model [8] and the multiframe process model [1] in uniprocessor environments. The schedulability tests are shown to be more precise and efficient than any existing polynomial-time schedulability tests. Moreover, the tests can be done Incrementally as each new task arrives at the system. Our proposed tests can also be used for the multiframe model where a task may have different computation times in different periods. We show the performance of the proposed schedulability tests In several simulation experiments.

Original languageEnglish
Pages (from-to)734-751
Number of pages18
JournalIEEE Transactions on Software Engineering
Issue number8
StatePublished - Aug 2003


  • Division graph
  • MPEG streams
  • Multiframe process
  • Open system environment
  • Real-time systems
  • Reduced set
  • Schedulability test
  • Time reservation


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