Confidence in Timing
Abstract
All contemporary safety standards require to demonstrate the absence of functional and non-functional safety hazards. In real-time systems this includes demonstrating the absence of critical timing hazards. To meet this veri cation objective it is necessary to show the correctness of the timing behavior with adequate con dence. Adequate con dence means that the evidence provided can be trusted beyond reasonable doubt. There are two main sources of doubt: the logic doubt associated with the validity of the reasoning and the epistemic doubt associated with uncertainty about the underlying assumptions. A fundamental timing property is the per-task worst-case execution (WCET). It is an ingredient for determining all higher-level timing concepts like worst-case response times, and system-wide end-to-end times. This article gives an overview of the challenges in ensuring timeliness of real-time software focusing on the worst-case execution time problem. It describes the principles of abstract interpretation-based WCET analysis and summarizes the con dence argument for applying it in the certi cation process of safety-critical software, addressing both logic and epistemic doubt.
Domains
Embedded Systems
Origin : Files produced by the author(s)
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