Guaranteeing some service upon mode switch in mixed-criticality - PowerPoint PPT Presentation

Guaranteeing some service upon mode switch in mixed-criticality systems Zhishan Guo Department of Computer Science, Missouri S&T Presented at Dagstuhl Seminar 17131 Mar. 28, 2017

MC & Vestal’s Interpretation • MC: functionalities of different criticality are implemented upon a shared platform. • Vestal Model – Multiple WCET estimations for each task – Execution of tasks may trigger a mode switch, where correctness is guaranteed at a different level Static Analysis; Pessimistic Mode switch C i H C i L t Measurement Based; Optimistic

MC & Vestal’s Interpretation • MC: functionalities of different criticality are implemented upon a shared platform. • Vestal Model – Multiple WCET estimations for each task – Execution of tasks may trigger a mode switch, where correctness is guaranteed at a different level Criticality Normal HI-Criticality Level mode mode HI tasks LO tasks NO GUARANTEE: LO tasks are abandoned!

MC & Vestal’s Interpretation • MC: functionalities of different criticality are implemented upon a shared platform. • Generalized Vestal Model – Multiple WCET estimations for each task – Execution of tasks may trigger a mode switch, where correctness is guaranteed at a different level Criticality Normal HI-Criticality Level mode mode HI tasks LO tasks Goal: GUARANTEE Some Service

MC Models • Vestal Model Mode switch C i H HI task C i L t LO task C i L t Criticality Normal HI-Crit. Level mode mode HI tasks C i L C i H LO tasks C i L 0

MC Models • Vestal Model • Our Model 1 Mode switch Mode switch C i H C i H HI task HI task C i L C i L t t GUARANTEE Some Service under HI mode LO task C i H C i L LO task C i L t t Criticality Normal HI-Crit. Criticality Normal HI-Crit. Level mode mode Level mode mode HI tasks HI tasks C i L C i H C i L C i H LO tasks LO tasks C i L C i H C i L 0 1. Sanjoy Baruah, Alan Burns, and Zhishan Guo . Scheduling mixed-criticality systems to guarantee some service under all non-erroneous behaviors. ECRTS'16

About MC-Fluid Fluid Scheduling Model • – Provide ideal schedule for multiprocessor – Each task τ i executes at a given rate θ i • MC-Fluid Scheduling Model – A task τ i is executed with L under normal mode · LO-rate θ i H after mode switch · HI-rate θ i Mode Switch Static Analysis; Pessimistic Speedup ≤ (√5 +1)/2 ≈ 1.62 C i H HI task [Lee et al., RTSS’14] C i L Speedup = 4/3 (Optimal) t [Baruah et al., RTSS’15] Measurement Based; Optimistic

MC-Fluid Our Algorithm 1 for Vestal Tasks • Fluid Scheduling Model – Provide ideal schedule for multiprocessor – Each task τ i executes at a given rate θ i U L H = Σ χ =LO u i H • MC-Fluid Scheduling Model – A task τ i is executed with L under normal mode · LO-rate θ i H after mode switch · HI-rate θ i RESERVED: θ i H C i H LO task LO task ~ C i L C i L π ~ t t π Mode switch Mode switch ~ C i C i H H HI task HI task ~ C i L C i L t t 1. Sanjoy Baruah, Alan Burns, and Zhishan Guo . Scheduling mixed-criticality systems to guarantee some service under all non-erroneous behaviors. ECRTS'16

MC & Vestal’s Interpretation • MC: functionalities of different criticality are implemented upon a shared platform. • Generalized Vestal Model H for LO-Criticality task (or a longer period) – C i • MC-Fluid -> DB-Fair or BFair / EDF-VD 2 – (m,k)- firm deadline (≠ longer period) Criticality Normal HI-Criticality Level mode mode HI tasks LO tasks 2. D. Liu, J. Spasic, N. Guan, G. Chen, S. Liu, T. Stefanov, and W. Yi. Goal: GUARANTEE Some Service EDF-VD Scheduling of Mixed-Criticality Systems with Degraded Quality Guarantees. RTSS 2016.

Thank you! Zhishan Guo guozh@mst.edu Mar. 29, 2017

Acknowledgement • Prof. Sanjoy Baruah, UNC Chapel Hill (Ph.D. advisor) • Prof. Nathan Fisher, Wayne State U • Prof. Luca Santinelli, ONERA France • Prof. Mohammed Al Faruque, UC Irvine • Dr. Zhenkai Zhang, Vanderbilt U • Prof. Abusayeed Saifullah, Wayne State U • Prof. Sajal Das, MST • Prof. Haoyi Xiong, MST • Ms. Sai Sruti, MST • Mr. Ashik Bhuiyan, MST

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