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Main Authors: Gao, Yiyang, Zhao, Shuai, Li, Boyang, Fang, Xinwei, Lin, Zhiyang, Jiang, Zhe, Guan, Nan
Format: Preprint
Published: 2025
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Online Access:https://arxiv.org/abs/2504.03754
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author Gao, Yiyang
Zhao, Shuai
Li, Boyang
Fang, Xinwei
Lin, Zhiyang
Jiang, Zhe
Guan, Nan
author_facet Gao, Yiyang
Zhao, Shuai
Li, Boyang
Fang, Xinwei
Lin, Zhiyang
Jiang, Zhe
Guan, Nan
contents Parallel real-time systems (e.g., autonomous driving systems) often contain functionalities with complex dependencies and execution uncertainties, leading to significant timing variability which can be represented as a probabilistic distribution. However, existing timing analysis either produces a single conservative bound or suffers from severe scalability issues due to the exhaustive enumeration of every execution scenario. This causes significant difficulties in leveraging the probabilistic timing behaviours, resulting in sub-optimal design solutions. Modelling the system as a probabilistic directed acyclic graph (p-DAG), this paper presents a probabilistic response time analysis based on the longest paths of the p-DAG across all execution scenarios, enhancing the capability of the analysis by eliminating the need for enumeration. We first identify every longest path based on the structure of p-DAG and compute the probability of its occurrence. Then, the worst-case interfering workload is computed for each longest path, forming a complete probabilistic response time distribution with correctness guarantees. Experiments show that compared to the enumeration-based approach, the proposed analysis effectively scales to large p-DAGs with computation cost reduced by six orders of magnitude while maintaining a low deviation (1.04% on average and below 5% for most p-DAGs), empowering system design solutions with improved resource efficiency.
format Preprint
id arxiv_https___arxiv_org_abs_2504_03754
institution arXiv
publishDate 2025
record_format arxiv
spellingShingle Exploiting the Uncertainty of the Longest Paths: Response Time Analysis for Probabilistic DAG Tasks
Gao, Yiyang
Zhao, Shuai
Li, Boyang
Fang, Xinwei
Lin, Zhiyang
Jiang, Zhe
Guan, Nan
Distributed, Parallel, and Cluster Computing
Parallel real-time systems (e.g., autonomous driving systems) often contain functionalities with complex dependencies and execution uncertainties, leading to significant timing variability which can be represented as a probabilistic distribution. However, existing timing analysis either produces a single conservative bound or suffers from severe scalability issues due to the exhaustive enumeration of every execution scenario. This causes significant difficulties in leveraging the probabilistic timing behaviours, resulting in sub-optimal design solutions. Modelling the system as a probabilistic directed acyclic graph (p-DAG), this paper presents a probabilistic response time analysis based on the longest paths of the p-DAG across all execution scenarios, enhancing the capability of the analysis by eliminating the need for enumeration. We first identify every longest path based on the structure of p-DAG and compute the probability of its occurrence. Then, the worst-case interfering workload is computed for each longest path, forming a complete probabilistic response time distribution with correctness guarantees. Experiments show that compared to the enumeration-based approach, the proposed analysis effectively scales to large p-DAGs with computation cost reduced by six orders of magnitude while maintaining a low deviation (1.04% on average and below 5% for most p-DAGs), empowering system design solutions with improved resource efficiency.
title Exploiting the Uncertainty of the Longest Paths: Response Time Analysis for Probabilistic DAG Tasks
topic Distributed, Parallel, and Cluster Computing
url https://arxiv.org/abs/2504.03754