Bounding Worst-Case Response Time for Tasks with Non-Preemptive Regions

Real-time schedulability theory requires a priori knowledge of the worst-case execution time (WCET) of every task in the system. Fundamental to the calculation of WCET is a scheduling policy that determines priorities among tasks. Such policies can be non-preemptive or preemptive. While the former reduces analysis complexity and overhead in implementation, the latter provides increased flexibility in terms of schedulability for higher utilizations of arbitrary task sets. In practice, tasks often have non-preemptive regions but are otherwise scheduled preemptively. To bound the WCET of tasks, architectural features have to be considered in the context of a scheduling scheme. In particular, preemption affects caches, which can be modeled by bounding the cache-related preemption delay (CRPD) of a task. In this paper, we propose a framework that provides safe and tight bounds of the data-cache related preemption delay (D-CRPD), the WCET and the worst-case response times, not just for hom...

• Type: Conference
• Year: 2008
• Where: RTAS
• Authors: Harini Ramaprasad, Frank Mueller
• Keywords: Non-preemptive Region, Preemption Delay, Real-Time Technology, RTAS 2008, Task Sets