Exact Interference of Adaptive Variable-Rate Tasks under Fixed-Priority Scheduling

Biondi, Alessandro; Melani, Alessandra; Marinoni, Mauro; Natale, Marco Di; Buttazzo, Giorgio

doi:10.1109/ecrts.2014.38

Cited by 31 publications

(36 citation statements)

References 14 publications

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“…By restricting to a finite set of dominant speeds [5], it is possible to limit the number of speed evolution patterns that have to be examined for deriving the worst-case interference. In [6] the response time computation has been approached as a search problem in the speed domain: the notion of dominant speeds is first used to reduce the number of critical instants (i.e., the situation in which all tasks are released simultaneously) and then the search space is reduced to dominant speeds only.…”

Section: A Schedulability Analysis Of Avr Tasksmentioning

confidence: 99%

“…The exact characterization of the interference produced by an AVR task under fixed priorities has been presented by Biondi et al [5] as a search approach in the speed domain, where the concept of dominant speeds is used to reduce the complexity and avoid speed quantization. Such a method has then been extended to derive an exact response time analysis of fixed priorities AVR tasks [6].…”

Section: Introductionmentioning

confidence: 99%

See 1 more Smart Citation

Performance-Driven Design of Engine Control Tasks

Biondi¹,

Natale²,

Buttazzo³

2016

2016 ACM/IEEE 7th International Conference on Cyber-Physical Systems (ICCPS)

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Engine control tasks include computational activities triggered at specific rotation angles of the crankshaft, making the computational load increase with the engine speed. To avoid overload at high speeds, simplified control implementations are used, defining different operational modes at different speed intervals. The design of a set of adaptive variable rate tasks is an optimization problem, consisting in determining the rotation speeds at which mode changes should occur to optimize the system performance while guaranteeing the schedulability. This paper presents three methods for tackling the optimization problem under a set of assumptions about the performance metric and the problem constraints. Two are heuristics and one is a branch and bound that is guaranteed, when it terminates, to find the optimum within a given granularity. In addition, a simple method to compute a performance upper bound is presented. The analysis of the problem reveals several insights for the design and the heuristics are shown to be quite close to the performance upper bound and the optimum with finite granularity.

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Section: A Schedulability Analysis Of Avr Tasksmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Performance-Driven Design of Engine Control Tasks

Biondi¹,

Natale²,

Buttazzo³

2016

2016 ACM/IEEE 7th International Conference on Cyber-Physical Systems (ICCPS)

Self Cite

View full text Add to dashboard Cite

show abstract

“…An exact characterization of the interference produced by an AVR task under fixed priorities has been presented by Biondi et al [2], who used a search approach in the speed domain, making use of dominant speeds to reduce complexity and avoid speed quantization.…”

Section: Introductionmentioning

confidence: 99%

Response-time analysis for real-time tasks in engine control applications

Biondi

Natale

Buttazzo

2015

Proceedings of the ACM/IEEE Sixth International Conference on Cyber-Physical Systems

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Engine control systems include computational activities that are triggered at predetermined angular values of the crankshaft, and therefore generate a workload that tends to increase with the engine speed. To cope with overload conditions, a common practice adopted by the automotive industry is to design such angular tasks with a set of modes that switch at given rotation speeds to adapt the computational demand. For this reason, these tasks are referred to as adaptive variable-rate (AVR). This paper presents an exact response time analysis for engine control applications consisting of periodic and AVR tasks scheduled by fixed priority. The proposed analysis is first presented for task sets with a single AVR task, and then extended to consider multiple AVR tasks related to a common rotation source. A number of experimental results are reported to validate the proposed approach and compare it against an existing sufficient test.

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“…Such mode changes can be found in the generalized multiframe (GMF) model [3], digraph real-time model (DRT) [23], and variable rate-dependent behavior (VRB) task model [6], [8], [10], [13]. The generalized multiframe (GMF) model [3] allows a task to cycle through a static list of job types, each with potentially different WCET bounds and relative deadlines.…”

Section: Introductionmentioning

confidence: 99%

“…Thus their activation rate is proportional to the angular velocity of a specific device. In such a system a common practice is to design a rate-dependent task, called variable rate-dependent behavior (VRB) task model [6], [8], [10], [13]. Typically, at lower rotation some functions that minimize fuel consumption and emissions have to be executed, whereas they are shed at higher rotation speeds to reduce the processor utilization.…”

Section: Introductionmentioning

confidence: 99%

Techniques for Schedulability Analysis in Mode Change Systems under Fixed-Priority Scheduling

Huang

Chen

2015

2015 IEEE 21st International Conference on Embedded and Real-Time Computing Systems and Applications

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With the advent of cyber-physical systems, realtime tasks shall be run in different modes over time to react to the change of the physical environment. It is preferable to adopt high expressive models in real-time systems. In the light of simple implementation in kernels, fixed-priority scheduling has been widely adopted in commercial real-time systems. In this work we derive a technique for analyzing schedulability of the system where tasks can undergo mode change under fixed-priority scheduling. We study two types of fixed-priority scheduling in mode change systems: task-level and mode-level fixed-priority scheduling. The proposed tests run in polynomial time. We further show that a utilization of 2 − √ 2 ≈ 0.5857 can be guaranteed in implicit-deadline multi-mode systems if each mode is prioritized according to rate-monotonic policy. The effectiveness of the proposed tests is also shown via extensive simulation results.

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Exact Interference of Adaptive Variable-Rate Tasks under Fixed-Priority Scheduling

Cited by 31 publications

References 14 publications

Performance-Driven Design of Engine Control Tasks

Performance-Driven Design of Engine Control Tasks

Response-time analysis for real-time tasks in engine control applications

Techniques for Schedulability Analysis in Mode Change Systems under Fixed-Priority Scheduling

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