Abstract
Mixing workloads with multiple criticality levels raises challenges both in timing analysis and schedulability analysis. The timing models have to characterize the different behaviors that real-time tasks can experience under the various criticality modes. Instead, the schedulability analysis has to combine every task and task interactions providing several guarantees, depending on the criticality level demanded at runtime. With this work, at first we propose representations to model every possible system criticality mode as a combination of task criticality modes. A set of bounding functions is obtained, a bound for each mode combination thus corresponding to a system criticality level. Secondly, we develop the schedulability analysis that applies such sets and derives schedulability conditions with mixed criticalities. The tasks are scheduled with fixed priority and earlies deadline first, and various levels of schedulability are defined from the mode combinations. Finally, we make use of the sensitivity analysis to evaluate the impact that multi mode task behaviors have on schedulability. Trade-offs between schedulability, criticality levels and resource availability are explored. A mixed critical real-time system case study validates the framework proposed.
Highlights
An increasingly important trend in developing real-time systems is the integration of applications with different levels of criticality
We have developed Mixed Criticality (MC) models with workloads and demand bound functions that bound criticality mode combinations and define multiple system criticality levels
The schedulability analyses we proposed make use of the MC models and apply them to Fixed Priority (FP) and Earliest Deadline First (EDF)
Summary
An increasingly important trend in developing real-time systems is the integration of applications with different levels of criticality. The criticality designs the level of assurance needed for a system element against failure e.g., standards ISO 26262, DO 178C, and IEC 61508. A Mixed Criticality (MC) real-time system is one that has two or more distinct criticality levels e.g., safety critical, mission critical, and/or low-critical. Such systems are defined to execute in a number of criticality modes, each mode specifying execution conditions and system criticalities. Please refer to [15] for a good overview of the MC problems for real-time systems
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Disclaimer: All third-party content on this website/platform is and will remain the property of their respective owners and is provided on "as is" basis without any warranties, express or implied. Use of third-party content does not indicate any affiliation, sponsorship with or endorsement by them. Any references to third-party content is to identify the corresponding services and shall be considered fair use under The CopyrightLaw.