wanja hofer, daniel lohmann, fabian scheler, … · sloth: let the hardware do the work! wanja...
TRANSCRIPT
Sloth: Let the Hardware Do the Work!
Wanja Hofer, Daniel Lohmann, Fabian Scheler,Wolfgang Schroder-Preikschat
SOSP 2009, WiP Session
Confessions of a Slothful
Wanja Hofer Sloth: Let the Hardware Do the Work! (SOSP-WiP 2009) 2
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
Let the Hardware Do the Work!
Wanja Hofer Sloth: Let the Hardware Do the Work! (SOSP-WiP 2009) 4
Sloth: Threads as Interrupts
Idea: Let interrupt subsystem do the schedulingand dispatching work
New: All threads are interrupt handlers andhave interrupt priorities
New: setReady(thread) is implemented as anIRQ
Wanja Hofer Sloth: Let the Hardware Do the Work! (SOSP-WiP 2009) 5
Sloth: Design and Example
IRQ SourceThread A
prio=1
request
IRQ SourceThread B
prio=2
request
IRQ SourceThread C
prio=3
request
IRQArbi-
trationUnit
CPU
curprio=X
IRQ VectorTable
threadA()
threadB()
threadC()
Wanja Hofer Sloth: Let the Hardware Do the Work! (SOSP-WiP 2009) 6
Sloth: Design and Example
IRQ SourceThread A
prio=1
request
IRQ SourceThread B
prio=2
request
IRQ SourceThread C
prio=3
request
IRQArbi-
trationUnit
CPU
curprio=1
IRQ VectorTable
threadA()
threadB()
threadC()
Wanja Hofer Sloth: Let the Hardware Do the Work! (SOSP-WiP 2009) 6
Sloth: Design and Example
IRQ SourceThread A
prio=1
request
IRQ SourceThread B
prio=2
request
IRQ SourceThread C
prio=3
request
IRQArbi-
trationUnit
CPU
curprio=1
IRQ VectorTable
threadA()
threadB()
threadC()
Wanja Hofer Sloth: Let the Hardware Do the Work! (SOSP-WiP 2009) 6
Sloth: Design and Example
IRQ SourceThread A
prio=1
request
IRQ SourceThread B
prio=2
request
IRQ SourceThread C
prio=3
request
IRQArbi-
trationUnit
CPU
curprio=3
IRQ VectorTable
threadA()
threadB()
threadC()
Wanja Hofer Sloth: Let the Hardware Do the Work! (SOSP-WiP 2009) 6
Sloth: Design and Example
IRQ SourceThread A
prio=1
request
IRQ SourceThread B
prio=2
request
IRQ SourceThread C
prio=3
request
IRQArbi-
trationUnit
CPU
curprio=3
IRQ VectorTable
threadA()
threadB()
threadC()
Wanja Hofer Sloth: Let the Hardware Do the Work! (SOSP-WiP 2009) 6
Sloth: Design and Example
IRQ SourceThread A
prio=1
request
IRQ SourceThread B
prio=2
request
IRQ SourceThread C
prio=3
request
IRQArbi-
trationUnit
CPU
curprio=3
IRQ VectorTable
threadA()
threadB()
threadC()
Wanja Hofer Sloth: Let the Hardware Do the Work! (SOSP-WiP 2009) 6
Sloth: Design and Example
IRQ SourceThread A
prio=1
request
IRQ SourceThread B
prio=2
request
IRQ SourceThread C
prio=3
request
IRQArbi-
trationUnit
CPU
curprio=2
IRQ VectorTable
threadA()
threadB()
threadC()
Wanja Hofer Sloth: Let the Hardware Do the Work! (SOSP-WiP 2009) 6
Sloth: Design and Example
IRQ SourceThread A
prio=1
request
IRQ SourceThread B
prio=2
request
IRQ SourceThread C
prio=3
request
IRQArbi-
trationUnit
CPU
curprio=1
IRQ VectorTable
threadA()
threadB()
threadC()
Wanja Hofer Sloth: Let the Hardware Do the Work! (SOSP-WiP 2009) 6
Sloth: Advantages
Simple
Small
Fast (2–20x)
Cool
Wanja Hofer Sloth: Let the Hardware Do the Work! (SOSP-WiP 2009) 7
Sloth: One of the Seven Deadly Sins
David Fincher, Se7en (1995)
Nicolas le Rouge, Le GrantKalendrier Des Bergiers (1496)
Wanja Hofer Sloth: Let the Hardware Do the Work! (SOSP-WiP 2009) 8
Sloth: One of the Seven Deadly Sins
David Fincher, Se7en (1995) Nicolas le Rouge, Le GrantKalendrier Des Bergiers (1496)
Wanja Hofer Sloth: Let the Hardware Do the Work! (SOSP-WiP 2009) 8
More About Being a Sloth
1. Talk to me!
2. http://www4.cs.fau.de/Research/Sloth/
Wanja Hofer Sloth: Let the Hardware Do the Work! (SOSP-WiP 2009) 9