Designing time partitions for real-time hypervisor with sufficient temporal independence

Virtualization techniques for embedded real-time systems, as known from the Integrated Modular Avionics (IMA) architecture of the ARINC653 standard, typically employ a TDMA scheduling to achieve temporal isolation among different virtualized partitions. Due to the fixed TDMA schedule, the worst case interrupt response times are significantly increased. An already proposed technique to mitigate this problem is to allow interrupts within an TDMA schedule, in order to achieve better interrupt response times while maintaining a sufficient degree of temporal independence via monitoring. In this paper we propose a novel approach that optimizes the TDMA schedule based on the partitions internal timing behavior and tasks parameters. The developed optimization algorithm generates a maximum amount of slack within the TDMA cycle. This slack is later used to interpose interrupts, while maintaining the interference with a monitor. We show correctness of the approach and evaluate it in a hypervisor implementation.