Operating Energy-Neutral Real-Time Systems

Wägemann, Peter; Distler, Tobias; Janker, Heiko; Raffeck, Phillip; Sieh, Volkmar; Schröder-Preikschat, Wolfgang

doi:10.1145/3078631

Cited by 6 publications

(3 citation statements)

References 22 publications

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“…Slack is an undesired property of resource-constrained systems since these systems aim to exploit best the available resources. In order to mitigate this problem of slack and support efficient operation, the dissertation presents the EnOS operating-system kernel [29,30]. The basic idea of EnOS is the awareness of mentioned analysis pessimism.…”

Section: Making Use Of Analysis Pessimism On System Levelmentioning

confidence: 99%

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Static Worst-Case Analyses and Their Validation Techniques for Safety-Critical Systems

Wägemann

2022

Ernst Denert Award for Software Engineering 2020

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The reliable operation of systems with both timing and energy requirements is a fundamental challenge in the area of safety-critical embedded systems. In order to provide guarantees for the execution of tasks within given resource budgets, these systems demand bounds of the worst-case execution time (WCET) and the worst-case energy consumption (WCEC). While static WCET analysis techniques are well established in the software development process of real-time systems nowadays, these program analysis techniques are not directly applicable to the fundamentally different behavior of energy consumption and the determination of the WCEC. Besides the missing approaches for WCEC bounds, the domain of worst-case analyses generally faces the problem that the accuracy and validity of reported analysis bounds are unknown: Since the actual worst-case resource consumption of existing benchmark programs cannot be automatically determined, a comprehensive validation of these program analysis tools is not possible.This summary of my dissertation addresses these problems by first describing a novel program analysis approach for WCEC bounds, which accounts for temporarily power-consuming devices, scheduling with fixed real-time priorities, synchronous task activations, and asynchronous interrupt service routines. Regarding the fundamental problem of validating worst-case tools, this dissertation presents a technique for automatically generating benchmark programs. The generator combines program patterns so that the worst-case resource consumption is available along with the generated benchmark. Knowledge about the actual worst-case resource demand then serves as the baseline for evaluating and validating program analysis tools. The fact the benchmark generator helped to reveal previously undiscovered software bugs in a widespread WCET tool for safety-critical systems underlines the relevance of such a structured testing technique.

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Section: Making Use Of Analysis Pessimism On System Levelmentioning

confidence: 99%

“…3. The operating-system kernel EnOS supports the reliable operation of systems with both timing and energy constraints based on a priori knowledge of WCET and WCEC bounds [29,30].…”

Section: Introductionmentioning

confidence: 99%

Static Worst-Case Analyses and Their Validation Techniques for Safety-Critical Systems

Wägemann

2022

Ernst Denert Award for Software Engineering 2020

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“…The real time kernel Energy Neutral Operating system ( EnOS ) [31] adapts energy consumption of high-end APs triggering the energy supply from an additional battery. Our hardware mechanism does not need EnOS or other software and can be applied to any AP.…”

Section: Introductionmentioning

confidence: 99%

Hardware Mechanism for Energy Saving in WiFi Access Points

Baquerizo

Suárez

Macías

et al. 2019

Sensors

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Wireless fidelity (WiFi) networks are deployed in several varied environments all around the World. Usually, the wireless fidelity access points are always on in houses and other small companies. In buildings of large companies and public organizations and in university campuses the number of access points is elevated; they are powered using power over the ethernet and are always on. Consequently, they consume a considerable amount of electric energy. The last versions of the International Electric and Electronic Engineers 802.11 standardized procedures to save energy in a wireless fidelity terminal but not in the access point. We designed a formal method to show when energy can be saved in wireless fidelity access points considering different power supplies for the access point: an electric energy battery and a standard voltage supply. We use an external battery that stores electric energy during an interval of time from a standard voltage supply (Charge period). After that interval (Discharge period), the energy supply for the access point is the external battery. Those intervals of time are repeated sequentially (Charge and Discharge cycles). We verified our formal model implementing a hardware circuit that controls the power supply for the access point. The amount of energy saving for a large number of of access points during a long period of time is considerably high.

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