AHA: Automated Hardware Abstraction in Operating-System Engineering (DFG: LO 1719/4-1)

Operating systems have always served the purpose to abstract and complement the capabilities of the underlying hardware. Conceptually, the operating system generalizes and expands the instruction set of the machine by partial interpretation and multiplexing of hardware resources. It simplifies the development and portability of applications by hiding the hardware from the application developer.

The price for abstraction and generalization are inefficiencies (with regard to storage requirements, energy requirements, eventuality, predictability, security, etc.) for the concrete application: The power of the generalized concepts is not fully used – but still provided. Hardware resources are virtualized by multiplexing – even in cases a direct mapping would be possible. Even in the OS implementation itself, the hardware is often not used directly, but again accessed via a further, partially interpreting hardware abstraction layer.

Our goal with AHA (Automated Hardware Abstraction in Operating System Design) is to improve nonfunctional properties of system software by a very deep, but fully automated specialization of the application-hardware bridge represented by the operating system. We want to investigate, how more directly mapped implementation variants of the "same" OS functionality – which are semantically equivalent (only) for a particular application – can be generated fully automatically from analyzing this application and its specific interactions with the operating system.

In the context of AHA, "Application" and "operating system functionality" covers the domain of embedded special purpose systems (automotive control unit, IoT device, embedded server node ...); "Hardware" stands for commercial-of-the-shelf platforms (Infineon AURIX, ARM, ...) using their specific characteristics as well as for completely application-specific processor hardware (such as RISC-V). In an extreme case, the specific operating-system functionality required by a particular application is instantiated directly into the command set and pipeline of the processors.

The application developer can – transparently – select among different specialization stages: from "classic" software-based specialization over application-/hardware-specific specialization on standard hardware up to the specialization of the hardware itself to cover the actually needed operating-system extensions.

The basic research question we want to answer with AHA is: What is the highest possible degree of application- and hardware-specific specialization and generalization of system software? Which efficiency gains can be achieved at what cost by problem-specific specialization, on the premise that the process of specialization can be performed completely automatically?

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OSPERT Workshop B
IRx: RTOS-Aware Abstract Interpretation using an LLVM-based Interpreter

Andreas Kässens, Vitali Fendel, Daniel LohmannProceedings of the 19th Annual Workshop on Operating Systems Platforms for Embedded Real-Time Applications (OSPERT '25)2025.
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@inproceedings{kaessens:25:ospert,
author = {Andreas Kässens and Vitali Fendel and Daniel Lohmann},
booktitle = {Proceedings of the 19th Annual Workshop on Operating Systems Platforms for Embedded Real-Time Applications (OSPERT '25)},
entrysubtype = {Workshop},
month = {July},
title = {{IRx}: {RTOS}-Aware Abstract Interpretation using an {LLVM}-based Interpreter},
venue = {Brussels, Belgium},
year = {2025},
}

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RTSJ Journal
Applied static analysis and specialization of cross-core syscalls for multi-core AUTOSAR OS

Gerion Entrup, Andreas Kässens, Björn Fiedler, Daniel LohmannReal-Time SystemsSpringer2024.
PDF 10.1007/s11241-024-09429-1 [BibTex]

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@article{entrup:24:rts,
author = {Gerion Entrup and Andreas Kässens and Björn Fiedler and Daniel Lohmann},
doi = {10.1007/s11241-024-09429-1},
entrysubtype = {Journal},
journaltitle = {Real-Time Systems},
month = {October},
options = {openaccess=doi},
publisher = {Springer},
title = {Applied static analysis and specialization of cross-core syscalls for multi-core {AUTOSAR OS}},
year = {2024},
}

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Thesis
Generische und betriebssystemgewahre statische Analysen von Echtzeitapplikationen auf Ein- und Mehrkernsystemen zur Optimierung nichtfunktionaler Eigenschaften

Gerion Entrup PHD thesisLeibniz Universität Hannover2024.
PDF Details Slides 10.15488/18718 [BibTex]

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@thesis{entrup:24:phd,
author = {Gerion Entrup},
doi = {10.15488/18718},
entrysubtype = {Thesis},
institution = {Leibniz Universität Hannover},
title = {Generische und betriebssystemgewahre statische Analysen von Echtzeitapplikationen auf Ein- und Mehrkernsystemen zur Optimierung nichtfunktionaler Eigenschaften},
year = {2024},
}

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RTAS Conference A
MultiSSE: Static Syscall Elision and Specialization for Event-Triggered Multi-Core RTOS

Gerion Entrup, Björn Fiedler, Daniel LohmannProceedings of the 29th IEEE Real-Time and Embedded Technology and Applications Symposium (RTAS'23)2023.
PDF Details Slides 10.1109/RTAS58335.2023.00028 [BibTex]

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@inproceedings{entrup:23:rtas,
author = {Gerion Entrup and Björn Fiedler and Daniel Lohmann},
booktitle = {Proceedings of the 29th IEEE Real-Time and Embedded Technology and Applications Symposium (RTAS'23)},
doi = {10.1109/RTAS58335.2023.00028},
entrysubtype = {Conference},
month = {May},
title = {{MultiSSE}: Static Syscall Elision and Specialization for Event-Triggered Multi-Core {RTOS}},
year = {2023},
}

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Thesis
Anwendungsgewahre statische Spezialisierung vormals dynamischer Systemaufrufe zur Verbesserung nichtfunktionaler Eigenschaften eingebetteter Echtzeitsysteme

Björn Fiedler PHD thesisLeibniz Universität Hannover2023.
PDF 10.15488/13945 [BibTex]

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@thesis{fiedler:23:phd,
author = {Björn Fiedler},
doi = {10.15488/13945},
entrysubtype = {Thesis},
institution = {Leibniz Universität Hannover},
title = {Anwendungsgewahre statische Spezialisierung vormals dynamischer Systemaufrufe zur Verbesserung nichtfunktionaler Eigenschaften eingebetteter Echtzeitsysteme},
year = {2023},
}

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OSPERT Workshop B
RTOS-Independent Interaction Analysis in ARA

Gerion Entrup, Jan Neugebauer, Daniel LohmannProceedings of the 16th Annual Workshop on Operating Systems Platforms for Embedded Real-Time Applications (OSPERT '22)2022.
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@inproceedings{entrup:22:ospert,
author = {Gerion Entrup and Jan Neugebauer and Daniel Lohmann},
booktitle = {Proceedings of the 16th Annual Workshop on Operating Systems Platforms for Embedded Real-Time Applications (OSPERT '22)},
entrysubtype = {Workshop},
month = {July},
title = {RTOS-Independent Interaction Analysis in ARA},
venue = {Modena, Italy},
year = {2022},
}

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ISORC Conference C Outstanding Paper Award
PSIC: Priority-Strict Multi-Core IRQ Processing

Malte Bargholz, Christian Dietrich, Daniel LohmannProceedings of the 25th International Symposium on Real-Time Distributed ComputingIEEE Computer Society2022Outstanding Paper Award.
PDF Slides 10.1109/ISORC52572.2022.9812796 [BibTex]

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@inproceedings{bargholz:22:isorc,
author = {Bargholz, Malte and Dietrich, Christian and Lohmann, Daniel},
booktitle = {Proceedings of the 25th International Symposium on Real-Time Distributed Computing},
doi = {10.1109/ISORC52572.2022.9812796},
entrysubtype = {Conference},
isbn = {978-1-6654-0627-7/22},
location = {Västerås, Sweden},
month = {May},
publisher = {{IEEE} Computer Society},
title = {PSIC: Priority-Strict Multi-Core IRQ Processing},
year = {2022},
}

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RTAS Conference A
ARA: Static Initialization of Dynamically-Created System Objects

Björn Fiedler, Gerion Entrup, Christian Dietrich, Daniel LohmannProceedings of the 27th IEEE Real-Time and Embedded Technology and Applications Symposium (RTAS'21)2021.
PDF Details Video Teaser Video 10.1109/RTAS52030.2021.00039 [BibTex]

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@inproceedings{fiedler:21:rtas,
author = {Björn Fiedler and Gerion Entrup and Christian Dietrich and Daniel Lohmann},
booktitle = {Proceedings of the 27th IEEE Real-Time and Embedded Technology and Applications Symposium (RTAS'21)},
doi = {10.1109/RTAS52030.2021.00039},
entrysubtype = {Conference},
month = {May},
pages = {400–412},
title = {{ARA}: Static Initialization of Dynamically-Created System Objects},
venue = {Virtual Event},
year = {2021},
}

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OSPERT Workshop B
ARA: Automatic Instance-Level Analysis in Real-Time Systems

Gerion Entrup, Benedikt Steinmeier, Christian DietrichProceedings of the 15th Annual Workshop on Operating Systems Platforms for Embedded Real-Time Applications (OSPERT '19)2019.
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@inproceedings{entrup:19:ospert,
author = {Gerion Entrup and Benedikt Steinmeier and Christian Dietrich},
booktitle = {Proceedings of the 15th Annual Workshop on Operating Systems Platforms for Embedded Real-Time Applications (OSPERT '19)},
entrysubtype = {Workshop},
month = {July},
title = {ARA: Automatic Instance-Level Analysis in Real-Time Systems},
venue = {Stuttgart, Germany},
year = {2019},
}

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RTSS Conference A*
RT.js: Practical Real-Time Scheduling for Web Applications

Christian Dietrich, Stefan Naumann, Robin Thrift, Daniel LohmannProceedings of the 40th IEEE Real-Time Systems Symposium 2019IEEE Computer Society Press2019.
PDF 10.1109/RTSS46320.2019.00017 [BibTex]

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@inproceedings{dietrich:19:rtss,
location = {Hong Kong, China},
author = {Christian Dietrich and Stefan Naumann and Robin Thrift and Daniel Lohmann},
booktitle = {Proceedings of the 40th IEEE Real-Time Systems Symposium 2019},
doi = {10.1109/RTSS46320.2019.00017},
entrysubtype = {Conference},
publisher = {IEEE Computer Society Press},
title = {RT.js: Practical Real-Time Scheduling for Web Applications},
year = {2019},
}

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OSPERT Workshop B Best Paper Award
Levels of Specialization in Real-Time Operating Systems

Björn Fiedler, Gerion Entrup, Christian Dietrich, Daniel LohmannProceedings of the 14th Annual Workshop on Operating Systems Platforms for Embedded Real-Time Applications (OSPERT '18)2018Best Paper Award.
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@inproceedings{fiedler:18:ospert,
author = {Björn Fiedler and Gerion Entrup and Christian Dietrich and Daniel Lohmann},
booktitle = {Proceedings of the 14th Annual Workshop on Operating Systems Platforms for Embedded Real-Time Applications (OSPERT '18)},
entrysubtype = {Workshop},
month = {July},
title = {Levels of Specialization in Real-Time Operating Systems},
venue = {Barcelona, Spain},
year = {2018},
}

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RTSS Conference A*
Semi-Extended Tasks: Efficient Stack Sharing Among Blocking Threads

Christian Dietrich, Daniel LohmannProceedings of the 39th IEEE Real-Time Systems Symposium 2018IEEE Computer Society Press2018.
PDF Details Slides Raw Data 10.1109/RTSS.2018.00049 [BibTex]

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@inproceedings{dietrich:18:rtss,
location = {Nashville, Tennessee, USA},
author = {Christian Dietrich and Daniel Lohmann},
booktitle = {Proceedings of the 39th IEEE Real-Time Systems Symposium 2018},
doi = {10.1109/RTSS.2018.00049},
editor = {Sebastian Altmeyer},
entrysubtype = {Conference},
publisher = {IEEE Computer Society Press},
title = {Semi-Extended Tasks: Efficient Stack Sharing Among Blocking Threads},
year = {2018},
}

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ECRTS Conference A Outstanding Paper Award
Whole-System Worst-Case Energy-Consumption Analysis for Energy-Constrained Real-Time Systems

Peter Wägemann, Christian Dietrich, Tobias Distler, Peter Ulbrich, Wolfgang Schröder-PreikschatProceedings of the 30th Euromicro Conference on Real-Time Systems 2018Schloss Dagstuhl–Leibniz-Zentrum fuer Informatik2018Outstanding Paper Award.
PDF 10.4230/LIPIcs.ECRTS.2018.24 [BibTex]

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@inproceedings{waegemann:18:ecrts,
author = {Peter Wägemann and Christian Dietrich and Tobias Distler and Peter Ulbrich and Wolfgang Schröder-Preikschat},
booktitle = {Proceedings of the 30th Euromicro Conference on Real-Time Systems 2018},
doi = {10.4230/LIPIcs.ECRTS.2018.24},
editor = {Sebastian Altmeyer},
entrysubtype = {Conference},
options = {openaccess=doi},
publisher = {Schloss Dagstuhl–Leibniz-Zentrum fuer Informatik},
title = {Whole-System Worst-Case Energy-Consumption Analysis for Energy-Constrained Real-Time Systems},
venue = {Barcelona, Spain},
year = {2018},
}

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FMCAD Conference
Automatic Verification of Application-Tailored OSEK Kernels

Hans-Peter Deifel, Christian Dietrich, Merlin Göttlinger, Daniel Lohmann, Stefan Milius, Lutz SchröderProceedings of the 17th Conference on Formal Methods in Computer-Aided Design (FMCAD '17)ACM Press2017.
PDF 10.23919/FMCAD.2017.8102260 [BibTex]

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@inproceedings{deifel:17:fmcad,
location = {New York, NY, USA},
author = {Hans-Peter Deifel and Christian Dietrich and Merlin Göttlinger and Daniel Lohmann and Stefan Milius and Lutz Schröder},
booktitle = {Proceedings of the 17th Conference on Formal Methods in Computer-Aided Design (FMCAD '17)},
doi = {10.23919/FMCAD.2017.8102260},
entrysubtype = {Conference},
month = {November},
pages = {1-8},
publisher = {ACM Press},
title = {Automatic Verification of Application-Tailored {OSEK} Kernels},
venue = {Vienna, Austria},
year = {2017},
}

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LCTES Conference A
OSEK-V: Application-Specific RTOS Instantiation in Hardware

Christian Dietrich, Daniel LohmannProceedings of the 2017 ACM SIGPLAN/SIGBED Conference on Languages, Compilers and Tools for Embedded Systems (LCTES '17)ACM Press2017.
PDF Raw Data 10.1145/3140582.3081030 [BibTex]

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BibTex Entry

@inproceedings{dietrich:17:lctes,
location = {New York, NY, USA},
ar = {25\% (13/56)},
author = {Christian Dietrich and Daniel Lohmann},
booktitle = {Proceedings of the 2017 ACM SIGPLAN/SIGBED Conference on Languages, Compilers and Tools for Embedded Systems (LCTES '17)},
category = {os-embedded, SRA},
doi = {10.1145/3140582.3081030},
entrysubtype = {Conference},
month = {June},
publisher = {ACM Press},
title = {{OSEK-V}: Application-Specific {RTOS} Instantiation in Hardware},
venue = {Barcelona, Spain},
year = {2017},
}

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TECS Journal A
Global Optimization of Fixed-Priority Real-Time Systems by RTOS-Aware Control-Flow Analysis

Christian Dietrich, Martin Hoffmann, Daniel LohmannACM Transactions on Embedded Computing Systems16.2ACM Press2017.
PDF Raw Data 10.1145/2950053 [BibTex]

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BibTex Entry

@article{dietrich:17:tecs,
location = {New York, NY, USA},
author = {Dietrich, Christian and Hoffmann, Martin and Lohmann, Daniel},
doi = {10.1145/2950053},
entrysubtype = {Journal},
journaltitle = {ACM Transactions on Embedded Computing Systems},
number = {2},
pages = {35:1–35:25},
publisher = {ACM Press},
title = {Global Optimization of Fixed-Priority Real-Time Systems by {RTOS}-Aware Control-Flow Analysis},
volume = {16},
year = {2017},
}

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ESE Invited Talk
SysWCET: Ende-zu-Ende-Antwortzeiten für OSEK-Systeme

Christian Dietrich, Peter WägemannTagungsband des Embedded Software Engineering Kongress 20172017.
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@inproceedings{dietrich:17:ese,
location = {Sindelfingen, Germany},
author = {Christian Dietrich and Peter Wägemann},
booktitle = {Tagungsband des Embedded Software Engineering Kongress 2017},
entrysubtype = {Invited Talk},
title = {SysWCET: Ende-zu-Ende-Antwortzeiten f{ü}r OSEK-Systeme},
year = {2017},
}

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RTAS Conference A Outstanding Paper Award
SysWCET: Whole-System Response-Time Analysis for Fixed-Priority Real-Time Systems

Christian Dietrich, Peter Wägemann, Peter Ulbrich, Daniel LohmannProceedings of the 23rd IEEE International Symposium on Real-Time and Embedded Technology and Applications (RTAS '17)IEEE Computer Society Press2017Outstanding Paper Award.
PDF Raw Data 10.1109/RTAS.2017.37 [BibTex]

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@inproceedings{dietrich:17:rtas,
location = {Washington, DC, USA},
ar = {},
author = {Christian Dietrich and Peter W{ä}gemann and Peter Ulbrich and Daniel Lohmann},
booktitle = {Proceedings of the 23rd IEEE International Symposium on Real-Time and Embedded Technology and Applications (RTAS '17)},
category = {WCET, WCRT, IPET, ILP},
doi = {10.1109/RTAS.2017.37},
entrysubtype = {Conference},
isbn = {978-1-5090-5269-1},
pages = {37-48},
publisher = {IEEE Computer Society Press},
title = {SysWCET: Whole-System Response-Time Analysis for Fixed-Priority Real-Time Systems},
year = {2017},
}

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