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 Ci

L

Ci

H

t Static Analysis; Pessimistic Measurement Based; Optimistic Mode switch

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 Level Normal mode HI-Criticality 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 Level Normal mode HI-Criticality mode HI tasks LO tasks

Goal: GUARANTEE Some Service

MC Models

• Vestal Model

Ci

L

Ci

H

t Mode switch HI task

Ci

L

t LO task

Criticality Level Normal mode HI-Crit. mode HI tasks

Ci

L

Ci

H

LO tasks

Ci

L

MC Models

• Vestal Model

Ci

L

Ci

H

t Mode switch HI task

• Our Model1

Ci

L

Ci

H

t Mode switch HI task

Ci

L

Ci

H

t LO task

Ci

L

t LO task

GUARANTEE Some Service under HI mode

Criticality Level Normal mode HI-Crit. mode HI tasks

Ci

L

Ci

H

LO tasks

Ci

L

Criticality Level Normal mode HI-Crit. mode HI tasks

Ci

L

Ci

H

LO tasks

Ci

L

Ci

H

• 1. Sanjoy Baruah, Alan Burns, and Zhishan Guo. Scheduling mixed-criticality systems to guarantee some service under all non-erroneous behaviors. ECRTS'16

• Fluid Scheduling Model

– Provide ideal schedule for multiprocessor – Each task τi executes at a given rate θi

• MC-Fluid Scheduling Model

– A task τi is executed with

· LO-rate θi

L under normal mode

· HI-rate θi

H after mode switch

About MC-Fluid

Speedup ≤ (√5 +1)/2 ≈ 1.62 [Lee et al., RTSS’14] Speedup = 4/3 (Optimal) [Baruah et al., RTSS’15]

Ci

L

Ci

H

t Mode Switch HI task Static Analysis; Pessimistic Measurement Based; Optimistic

RESERVED: θi

H

• Fluid Scheduling Model

– Provide ideal schedule for multiprocessor – Each task τi executes at a given rate θi

• MC-Fluid Scheduling Model

– A task τi is executed with

· LO-rate θi

L under normal mode

· HI-rate θi

H after mode switch

Our Algorithm1

Ci

L

Ci

H

t Mode switch HI task

Ci

L

Ci

H

t LO task Ci

L

Ci

H

t Mode switch HI task

Ci

L

t LO task

~ ~ ~ ~

π π

MC-Fluid

for

Vestal Tasks

UL

H=Σχ =LO ui H

• 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

– Ci

H for LO-Criticality task (or a longer period)

• MC-Fluid -> DB-Fair or BFair

/ EDF-VD2

– (m,k)-firm deadline (≠ longer period) Criticality Level Normal mode HI-Criticality mode HI tasks LO tasks

Goal: GUARANTEE Some Service

• 2. D. Liu, J. Spasic, N. Guan, G. Chen, S. Liu, T. Stefanov, and W. Yi.

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

Backup Slides

Motivation

• I think there is a world market for maybe five computers.
• Thomas Watson,

Chairman of IBM, 1943

• There is no reason anyone would want a computer in

their home.

• Ken Olson,

President of Digital Equipment Corporation, 1977

Missouri S&T Michigan Tech Colorado Mines SD Mines New Mexico Mining & Tech Illinois Tech Cal Tech Florida Tech Georgia Tech Clarkson New Jersey Tech Stevens Tech WPI Rensselaer U of A - Huntsville MIT

1,125 International Students in Fall 2016