Fixed-priority scheduling of dual-criticality systems

In modern embedded platforms, safety-critical functionalities that must be certified correct to very high levels of assurance may co-exist with less critical software that is not subject to certification requirements. One seeks to satisfy two, sometimes contradictory, goals upon such mixed-criticality platforms: (i) certify the safety-critical functionalities under very conservative assumptions, and (ii) achieve high resource utilization during run-time, when actual behavior does not live up to the pessimistic assumptions under which certification was made. This paper makes two contributions: (i) it surveys different fixed-priority scheduling algorithms that have been proposed, that seek to balance these two requirements, and (ii) it completes prior work that performs a comparative evaluation of these different fixed-priority scheduling algorithms. It particularly focuses upon the period transformation technique for dual-criticality scheduling, since this technique has received relatively less attention in prior work.