Foundational Response-Time Analysis as Explainable Evidence of Timeliness

Authors Marco Maida, Sergey Bozhko, Björn B. Brandenburg

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Author Details

Marco Maida
  • Max Planck Institute for Software Systems (MPI-SWS), Kaiserslautern, Germany
Sergey Bozhko
  • Max Planck Institute for Software Systems (MPI-SWS), Kaiserslautern, Germany
  • Saarbrücken Graduate School of Computer Science, Universität des Saarlandes, Germany
Björn B. Brandenburg
  • Max Planck Institute for Software Systems (MPI-SWS), Kaiserslautern, Germany


We thank Pierre Roux for introducing us to CoqEAL and the members of the joint ANR-DFG project RT-PROOFS for fruitful discussions.

Cite AsGet BibTex

Marco Maida, Sergey Bozhko, and Björn B. Brandenburg. Foundational Response-Time Analysis as Explainable Evidence of Timeliness. In 34th Euromicro Conference on Real-Time Systems (ECRTS 2022). Leibniz International Proceedings in Informatics (LIPIcs), Volume 231, pp. 19:1-19:25, Schloss Dagstuhl – Leibniz-Zentrum für Informatik (2022)


The paper introduces foundational response-time analysis (RTA) as a means to produce strong and independently checkable evidence of temporal correctness. In a foundational RTA, each response-time bound calculated comes with an auto-generated certificate of correctness - a short and human-inspectable sequence of machine-checked proofs that formally show the claimed bound to hold. In other words, a foundational RTA yields explainable results that can be independently verified (e.g., by a certification authority) in a rigorous manner (with an automated proof checker). Consequently, the analysis tool itself does not need to be verified nor trusted. As a proof of concept, the paper presents POET, the first foundational RTA tool. POET generates certificates based on Prosa, the to-date largest verified framework for schedulability analysis, which is based on Coq. The trusted computing base is hence reduced to the Coq proof checker and its dependencies. POET currently supports two scheduling policies (earliest-deadline-first, fixed-priority), two preemption models (fully preemptive, fully non-preemptive), arbitrary deadlines, periodic and sporadic tasks, and tasks characterized by arbitrary arrival curves. The paper describes the challenges inherent in the development of a foundational RTA tool, discusses key design choices, and reports on its scalability.

Subject Classification

ACM Subject Classification
  • Computer systems organization → Real-time systems
  • Software and its engineering → Formal software verification
  • hard real-time systems
  • response-time analysis
  • uniprocessor
  • Coq
  • Prosa
  • fixed priority
  • EDF
  • preemptive
  • non-preemptive
  • verification


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