,
Atsushi Yano
,
Takuya Azumi
Creative Commons Attribution 4.0 International license
Mixed-criticality DAG task systems on multiprocessors require schedulability analysis to guarantee that safety-critical tasks meet their deadlines. Conventional approaches rely on worst-case execution times (WCETs), which account for extremely rare pathological scenarios and consequently lead to significant over-provisioning of processor cores. This paper proposes a probabilistic schedulability analysis that exploits the statistical rarity of multiple vertices within a DAG exceeding their expected execution budgets. By grouping vertices within each DAG into small clusters and bounding the probability that more than one vertex in a cluster overruns, the method assigns each cluster a tighter execution budget than the sum of individual WCETs, thereby reducing the number of cores required. The clustering configuration is optimized via simulated annealing to minimize total core usage while maintaining a designer-specified bound on the system-level probability of deadline misses. Experiments on synthetic task sets demonstrate that the proposed method reduces the required number of cores by up to 36% compared to a deterministic baseline, with larger gains for DAGs exhibiting higher internal parallelism.
@InProceedings{takahashi_et_al:LIPIcs.ECRTS.2026.3,
author = {Takahashi, Hiroto and Yano, Atsushi and Azumi, Takuya},
title = {{Probabilistic Schedulability Analysis for Mixed-Criticality DAG Tasks on Multiprocessors}},
booktitle = {38th European Conference on Real-Time Systems (ECRTS 2026)},
pages = {3:1--3:23},
series = {Leibniz International Proceedings in Informatics (LIPIcs)},
ISBN = {978-3-95977-429-1},
ISSN = {1868-8969},
year = {2026},
volume = {375},
editor = {Kritikakou, Angeliki},
publisher = {Schloss Dagstuhl -- Leibniz-Zentrum f{\"u}r Informatik},
address = {Dagstuhl, Germany},
URL = {https://drops.dagstuhl.de/entities/document/10.4230/LIPIcs.ECRTS.2026.3},
URN = {urn:nbn:de:0030-drops-265871},
doi = {10.4230/LIPIcs.ECRTS.2026.3},
annote = {Keywords: Mixed-Criticality Systems, DAG Tasks, Probabilistic Analysis, Federated Scheduling, Real-Time Systems}
}