Estimating Probabilistic Safe WCET Ranges of Real-Time Systems at Design Stages
This addresses the challenge for real-time system engineers who need probabilistic safe WCET ranges to ensure system safety, representing an incremental improvement over existing methods.
The paper tackles the problem of estimating worst-case execution time (WCET) ranges for real-time systems at design stages, providing an automated technique that determines WCET values likely to meet deadlines with probabilistic guarantees, and it was evaluated on industrial and synthetic systems, showing efficient and accurate estimation.
Estimating worst-case execution times (WCET) is an important activity at early design stages of real-time systems. Based on WCET estimates, engineers make design and implementation decisions to ensure that task executions always complete before their specified deadlines. However, in practice, engineers often cannot provide precise point WCET estimates and prefer to provide plausible WCET ranges. Given a set of real-time tasks with such ranges, we provide an automated technique to determine for what WCET values the system is likely to meet its deadlines, and hence operate safely with a probabilistic guarantee. Our approach combines a search algorithm for generating worst-case scheduling scenarios with polynomial logistic regression for inferring probabilistic safe WCET ranges. We evaluated our approach by applying it to three industrial systems from different domains and several synthetic systems. Our approach efficiently and accurately estimates probabilistic safe WCET ranges within which deadlines are likely to be satisfied with a high degree of confidence.