Generalizing fixed-priority scheduling for better schedulability in mixed-criticality systems

• Different priority orderings are used to generalize mixed-criticality scheduling.
• A response time analysis is developed to guarantee certification requirements.
• A new priority assignment algorithm is proposed for determining task priority.
• The proposed solution outperforms existing approaches in terms of acceptance ratio.

The design of mixed-criticality systems is often subject to mandatory certification and has been drawing considerable attention over the past few years. This letter studies fixed-priority scheduling of mixed-criticality systems on a uniprocessor platform but in a more general way, using different priority orderings in different execution phases and considering them collectively. Then a sufficient response-time analysis is developed and a new priority assignment scheme is proposed. This generalized approach has potential in better schedulability performance for mixed-criticality systems.