Sloth : Let the Hardware Do the Work! Wanja Hofer , Daniel Lohmann, - - PowerPoint PPT Presentation

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sloth let the hardware do the work

Sloth : Let the Hardware Do the Work! Wanja Hofer , Daniel Lohmann, - - PowerPoint PPT Presentation

May 09, 2023 250 likes •434 views

Sloth : Let the Hardware Do the Work! Wanja Hofer , Daniel Lohmann, Fabian Scheler, Wolfgang Schr oder-Preikschat SOSP 2009, WiP Session Confessions of a Slothful Wanja Hofer Sloth : Let the Hardware Do the Work! (SOSP-WiP 2009) 2 How It

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Sloth: Let the Hardware Do the Work!

Wanja Hofer, Daniel Lohmann, Fabian Scheler, Wolfgang Schr¨

der-Preikschat

SOSP 2009, WiP Session

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Confessions of a Slothful

Wanja Hofer Sloth: Let the Hardware Do the Work! (SOSP-WiP 2009) 2

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How It All Began...

Building embedded OSes as used in automotive industry Prevalent OS standard: OSEK OS

Event-triggered, priority-driven real-time system

Wanja Hofer Sloth: Let the Hardware Do the Work! (SOSP-WiP 2009) 3

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Let the Hardware Do the Work!

Wanja Hofer Sloth: Let the Hardware Do the Work! (SOSP-WiP 2009) 4

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Sloth: Threads as Interrupts

Idea: Let interrupt subsystem do the scheduling and dispatching work New: All threads are interrupt handlers and have interrupt priorities New: setReady(thread) is implemented as an IRQ

Wanja Hofer Sloth: Let the Hardware Do the Work! (SOSP-WiP 2009) 5

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Sloth: Design and Example

IRQ Source Thread A prio=1 request IRQ Source Thread B prio=2 request IRQ Source Thread C prio=3 request IRQ Arbi- tration Unit CPU curprio=X IRQ Vector Table threadA() threadB() threadC()

Wanja Hofer Sloth: Let the Hardware Do the Work! (SOSP-WiP 2009) 6

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Sloth: Design and Example

IRQ Source Thread A prio=1 request IRQ Source Thread B prio=2 request IRQ Source Thread C prio=3 request IRQ Arbi- tration Unit CPU curprio=1 IRQ Vector Table threadA() threadB() threadC()

Wanja Hofer Sloth: Let the Hardware Do the Work! (SOSP-WiP 2009) 6

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Sloth: Design and Example

IRQ Source Thread A prio=1 request IRQ Source Thread B prio=2 request IRQ Source Thread C prio=3 request IRQ Arbi- tration Unit CPU curprio=1 IRQ Vector Table threadA() threadB() threadC()

Wanja Hofer Sloth: Let the Hardware Do the Work! (SOSP-WiP 2009) 6

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Sloth: Design and Example

IRQ Source Thread A prio=1 request IRQ Source Thread B prio=2 request IRQ Source Thread C prio=3 request IRQ Arbi- tration Unit CPU curprio=3 IRQ Vector Table threadA() threadB() threadC()

Wanja Hofer Sloth: Let the Hardware Do the Work! (SOSP-WiP 2009) 6

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Sloth: Design and Example

IRQ Source Thread A prio=1 request IRQ Source Thread B prio=2 request IRQ Source Thread C prio=3 request IRQ Arbi- tration Unit CPU curprio=3 IRQ Vector Table threadA() threadB() threadC()

Wanja Hofer Sloth: Let the Hardware Do the Work! (SOSP-WiP 2009) 6

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Sloth: Design and Example

IRQ Source Thread A prio=1 request IRQ Source Thread B prio=2 request IRQ Source Thread C prio=3 request IRQ Arbi- tration Unit CPU curprio=3 IRQ Vector Table threadA() threadB() threadC()

Wanja Hofer Sloth: Let the Hardware Do the Work! (SOSP-WiP 2009) 6

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Sloth: Design and Example

IRQ Source Thread A prio=1 request IRQ Source Thread B prio=2 request IRQ Source Thread C prio=3 request IRQ Arbi- tration Unit CPU curprio=2 IRQ Vector Table threadA() threadB() threadC()

Wanja Hofer Sloth: Let the Hardware Do the Work! (SOSP-WiP 2009) 6

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Sloth: Design and Example

IRQ Source Thread A prio=1 request IRQ Source Thread B prio=2 request IRQ Source Thread C prio=3 request IRQ Arbi- tration Unit CPU curprio=1 IRQ Vector Table threadA() threadB() threadC()

Wanja Hofer Sloth: Let the Hardware Do the Work! (SOSP-WiP 2009) 6

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Sloth: Advantages

Simple Small Fast (2–20x) Cool

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Sloth: One of the Seven Deadly Sins

David Fincher, Se7en (1995)

Wanja Hofer Sloth: Let the Hardware Do the Work! (SOSP-WiP 2009) 8

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Sloth: One of the Seven Deadly Sins

David Fincher, Se7en (1995) Nicolas le Rouge, Le Grant Kalendrier Des Bergiers (1496)

Wanja Hofer Sloth: Let the Hardware Do the Work! (SOSP-WiP 2009) 8

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More About Being a Sloth

1. Talk to me!
2. http://www4.cs.fau.de/Research/Sloth/

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