On Strong and Weak Sustainability, with an Application to Self-Suspending Real-Time Tasks
Ref: CISTER-TR-180502 Publication Date: 3 to 6, Jul, 2018
On Strong and Weak Sustainability, with an Application to Self-Suspending Real-Time TasksRef: CISTER-TR-180502 Publication Date: 3 to 6, Jul, 2018
Motivated by an apparent contradiction regarding whether certain scheduling policies are sustainable, we revisit the topic of sustainability in real-time scheduling and argue that the existing definitions of sustainability should be further clarified and generalized. After proposing a formal, generic sustainability theory, we relax the existing notion of (strongly) sustainable scheduling policy to provide a new classification called weak sustainability. Proving weak sustainability properties allows reducing the numb er of variables that must be considered in the search of a worst-case schedule, and hence enables more efficient schedulability analyses and testing regimes even for policies that are not (strongly) sustainable. As a proof of concept, and to better understand a model for which many mistakes were found in the literature, we study weak sustainability in the context of dynamic self-suspending tasks, where we formalize a generic suspension model using the Coq proof assistant and provide a machine-checked proof that any JLFP scheduling policy is weakly sustainable with respect to job costs and variable suspension times.
30th Euromicro Conference on Real-Time Systems (ECRTS 2018), pp 26:1-26:21.
Notes: Volume 106 Outstanding Paper Award