# A Necessary Test for Fixed-Priority Real-Time Multiprocessor Systems based on Lazy-adversary Simulation

### Romulo Silva de Oliveira, Andreu Carminati, Renan Starke

#### Abstract

Many embedded systems have real-time requirements which are sometimes hard and must be guaranteed at design time, although most embedded systems have soft deadlines in the sense that they can be missed without any catastrophe being caused by that. Scheduling simulations can be used as a necessary but not sufficient schedulability test that is useful for both hard and soft real-time systems. They help to assess the pessimism of formal analysis applied to hard real-time systems and they can be used as test-case generators during the design of soft real-time systems. In this paper, we present a new adversary simulator for multiprocessors with global task queue and fixed-priority scheduling. We consider sporadic tasks with constrained deadlines (D <= T). An adversary simulator uses the non-determinism in the arrivals of sporadic tasks to stress the system scheduler with valid arrival patterns. The simulator proposed in this paper applies a lazy approach that delays the arrival of high-priority tasks in order to form gangs that will preclude the execution of a victim task. We show that the new lazy-adversary simulator presented in this paper outperforms the previously existing necessary schedulability tests.

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#### Paper Citation

#### in Harvard Style

Silva de Oliveira R., Carminati A. and Starke R. (2014). **A Necessary Test for Fixed-Priority Real-Time Multiprocessor Systems based on Lazy-adversary Simulation** . In *Proceedings of the 4th International Conference on Simulation and Modeling Methodologies, Technologies and Applications - Volume 1: SIMULTECH,* ISBN 978-989-758-038-3, pages 321-329. DOI: 10.5220/0005008903210329

#### in Bibtex Style

@conference{simultech14,

author={Romulo Silva de Oliveira and Andreu Carminati and Renan Starke},

title={A Necessary Test for Fixed-Priority Real-Time Multiprocessor Systems based on Lazy-adversary Simulation},

booktitle={Proceedings of the 4th International Conference on Simulation and Modeling Methodologies, Technologies and Applications - Volume 1: SIMULTECH,},

year={2014},

pages={321-329},

publisher={SciTePress},

organization={INSTICC},

doi={10.5220/0005008903210329},

isbn={978-989-758-038-3},

}

#### in EndNote Style

TY - CONF

JO - Proceedings of the 4th International Conference on Simulation and Modeling Methodologies, Technologies and Applications - Volume 1: SIMULTECH,

TI - A Necessary Test for Fixed-Priority Real-Time Multiprocessor Systems based on Lazy-adversary Simulation

SN - 978-989-758-038-3

AU - Silva de Oliveira R.

AU - Carminati A.

AU - Starke R.

PY - 2014

SP - 321

EP - 329

DO - 10.5220/0005008903210329