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BOT-MICS: Bounding time using analytics in mixed-criticality systems

Ranjbar, B ; Sharif University of Technology | 2022

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  1. Type of Document: Article
  2. DOI: 10.1109/TCAD.2021.3127867
  3. Publisher: Institute of Electrical and Electronics Engineers Inc , 2022
  4. Abstract:
  5. An increasing trend for reducing cost, space, and weight leads to modern embedded systems that execute multiple tasks with different criticality levels on a common hardware platform while guaranteeing a safe operation. In such mixed-criticality (MC) systems, multiple worst case execution times (WCETs) are defined for each task, corresponding to the system operation mode to improve the MC system's timing behavior at runtime. Determining the appropriate WCETs for lower criticality (LC) modes is nontrivial. On the one hand, considering a very low WCET for tasks can improve the processor utilization by scheduling more tasks in that mode, on the other hand, using a larger WCET ensures that the mode switches (which causes by task overrunning) are minimized, thereby improving the quality of service for all tasks, albeit at the cost of processor utilization. Hitherto, no analytical solutions are proposed to determine WCETs in LC modes. In this regard, we propose a scheme to determine WCETs by the Chebyshev theorem, to make a tradeoff between the number of scheduled tasks at design-time and the number of dropped low-criticality tasks at runtime as a result of frequent mode switches. To have a tight bound of execution times and mode switching probability, we also propose a distribution analytics-based scheme, in which the mode switching probability is obtained based on the cumulative distribution function. Our experimental results show that our scheme improves the utilization of state-of-the-art MC systems by up to 72.27%, while maintaining 24.28% mode switching probability in the worst case scenario. Besides, the results of running embedded real-time benchmarks on a real platform show that the distribution-based scheme can improve the utilization by 7.30% while bounding the mode switching probability by 4.85% more, compared to the Chebyshev-based scheme. © 1982-2012 IEEE
  6. Keywords:
  7. Mixed-criticality (MC) ; optimization ; resource utilization ; worst case execution times (WCETs) analysis ; Cost benefit analysis ; Criticality (nuclear fission) ; Distribution functions ; Economic and social effects ; Embedded systems ; Interactive computer systems ; Quality of service ; Response time (computer systems) ; Switching ; Time switches ; Analyse ; Bad-case execution time’ ; Mixed criticalities ; Mode switching probability ; Mode-switching ; Optimisations ; Quality-of-service ; Real - Time system ; Resources utilizations ; Schedulability ; Switching probability ; Systems operation ; Task analysis ; Tight execution time bound ; Time bound ; Timing ; Worst-case execution time ; Real time systems
  8. Source: IEEE Transactions on Computer-Aided Design of Integrated Circuits and Systems ; Volume 41, Issue 10 , 2022 , Pages 3239-3251 ; 02780070 (ISSN)
  9. URL: https://ieeexplore.ieee.org/document/9612593