Improved response-time bounds in fixed priority scheduling with arbitrary deadlines

Grass, Werner; Nguyen, Thi Huyen Chau

doi:10.1007/s11241-017-9282-7

“…To investigate RQ3, we use synthetic subjects in order to freely control key parameters in real-time systems. We create a set of tasks by adopting a well-known procedure (Emberson et al 2010) for synthesizing real-time tasks, which has been applied in many schedulability analysis studies (Davis et al 2008;Zhang and Burns 2009;Davis and Burns 2011;Grass and Nguyen 2018;Durr et al 2019).…”

Section: Synthetic Study Subjectsmentioning

confidence: 99%

Optimal priority assignment for real-time systems: a coevolution-based approach

Lee

¹

,

Shin

²

,

Nejati

³

et al. 2022

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In real-time systems, priorities assigned to real-time tasks determine the order of task executions, by relying on an underlying task scheduling policy. Assigning optimal priority values to tasks is critical to allow the tasks to complete their executions while maximizing safety margins from their specified deadlines. This enables real-time systems to tolerate unexpected overheads in task executions and still meet their deadlines. In practice, priority assignments result from an interactive process between the development and testing teams. In this article, we propose an automated method that aims to identify the best possible priority assignments in real-time systems, accounting for multiple objectives regarding safety margins and engineering constraints. Our approach is based on a multi-objective, competitive coevolutionary algorithm mimicking the interactive priority assignment process between the development and testing teams. We evaluate our approach by applying it to six industrial systems from different domains and several synthetic systems. The results indicate that our approach significantly outperforms both our baselines, i.e., random search and sequential search, and solutions defined by practitioners. Our approach scales to complex industrial systems as an offline analysis method that attempts to find near-optimal solutions within acceptable time, i.e., less than 16 hours.

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“…To investigate RQ2, we use synthetic subjects in order to freely control key parameters in real-time systems. We create a set of tasks by adopting a wellknown procedure (Emberson et al, 2010) for synthesizing real-time tasks, which has been applied in many schedulability analysis studies (Davis et al, 2008;Zhang and Burns, 2009;Dürr et al, 2019;Grass and Nguyen, 2018;Davis and Burns, 2011). Figure 8 describes a procedure that synthesizes a set of real-time tasks.…”

Section: Synthetic Study Subjectsmentioning

confidence: 99%

Optimal Priority Assignment for Real-Time Systems: A Coevolution-Based Approach

Lee¹,

Shin²,

Nejati³

et al. 2021

Preprint

0

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In real-time systems, priorities assigned to real-time tasks determine the order of task executions, by relying on an underlying task scheduling policy. Assigning optimal priority values to tasks is critical to allow the tasks to complete their executions while maximizing safety margins from their specified deadlines. This enables real-time systems to tolerate unexpected overheads in task executions and still meet their deadlines. In practice, priority assignments result from an interactive process between the development and testing teams. In this article, we propose an automated method that aims to identify the best possible priority assignments in real-time systems, accounting for multiple objectives regarding safety margins and engineering constraints. Our approach is based on a multi-objective, competitive coevolutionary algorithm mimicking the interactive priority assignment process between the development and testing teams. We evaluate our approach by applying it to six industrial systems

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“…After these preparations we can now take the decisive third step in the proof of Theorem 1. First, a basic property of nested ceiling functions is recalled from Lemma 6 in [13]. Lemma 6.…”

Section: If We Start the Iteration For The Determination Of T I With ...mentioning

confidence: 99%

Exact Polynomial Time Algorithm for the Response Time Analysis of Harmonic Tasks with Constrained Release Jitter

Nguyen¹,

Grass²,

Jansen³

2019

Preprint

Self Cite

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In some important application areas of hard real-time systems, preemptive sporadic tasks with harmonic periods and constraint deadlines running upon a uniprocessor platform play an important role. We propose a new algorithm for determining the exact worst-case response time for a task that has a lower computational complexity (linear in the number of tasks) than the known algorithm developed for the same system class. We also allow the task executions to start delayed due to release jitter if they are within certain value ranges. For checking if these constraints are met we define a constraint programming problem that has a special structure and can be solved with heuristic components in a time that is linear in the task number. If the check determines the admissibility of the jitter values, the linear time algorithm can be used to determine the worst-case response time also for jitter-aware systems.

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Improved response-time bounds in fixed priority scheduling with arbitrary deadlines

Cited by 7 publications

References 31 publications

Optimal priority assignment for real-time systems: a coevolution-based approach

Optimal priority assignment for real-time systems: a coevolution-based approach

Optimal Priority Assignment for Real-Time Systems: A Coevolution-Based Approach

Exact Polynomial Time Algorithm for the Response Time Analysis of Harmonic Tasks with Constrained Release Jitter

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