Utilization-Based Scheduling of Flexible Mixed-Criticality Real-Time Tasks

Gang Chen, Nan Guan, Di Liu, Qingqiang He, Kai Huang, Todor Stefanov, Wang Yi

Research output: Journal article publicationJournal articleAcademic researchpeer-review

27 Citations (Scopus)


Mixed-criticality models are an emerging paradigm for the design of real-Time systems because of their significantly improved resource efficiency. However, formal mixed-criticality models have traditionally been characterized by two impractical assumptions: once any high-criticality task overruns, all low-criticality tasks are suspended and all other high-criticality tasks are assumed to exhibit high-criticality behaviors at the same time. In this paper, we propose a more realistic mixed-criticality model, called the flexible mixed-criticality (FMC) model, in which these two issues are addressed in a combined manner. In this new model, only the overrun task itself is assumed to exhibit high-criticality behavior, while other high-criticality tasks remain in the same mode as before. The guaranteed service levels of low-criticality tasks are gracefully degraded with the overruns of high-criticality tasks. We derive a utilization-based technique to analyze the schedulability of this new mixed-criticality model under EDF-VD scheduling. During run time, the proposed test condition serves an important criterion for dynamic service level tuning, by means of which the maximum available execution budget for low-criticality tasks can be directly determined with minimal overhead while guaranteeing mixed-criticality schedulability. Experiments demonstrate the effectiveness of the FMC scheme compared with state-of-The-Art techniques.
Original languageEnglish
Pages (from-to)543-558
Number of pages16
JournalIEEE Transactions on Computers
Issue number4
Publication statusPublished - 1 Apr 2018


  • EDF-VD scheduling
  • flexible mixed-criticality system
  • utilization-based analysis

ASJC Scopus subject areas

  • Software
  • Theoretical Computer Science
  • Hardware and Architecture
  • Computational Theory and Mathematics


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