1 What is the meaning of preemption in utility based real-time scheduling? Raphael Guerra Gerhard Fohler TU Kaiserslautern Germany.

1

What is the meaning of preemption in utility based

real-time scheduling?

Raphael GuerraGerhard Fohler

TU KaiserslauternGermany

2

Utility based models

task 2

utility model

execution window

task 1

deadlineearliest start time

uti

lity

utility accrual

+

_

Calculate utility accrualReference point?

Which?

3

Preemptions in utility model

task 2

execution window

task 1

uti

lity

utility accrual

+

_

4

Preemptions in utility model

task 2

execution window

task 1

uti

lity

Calculate utility accrualReference point?

Which?What happens on preemption?

utility accrual

+

_

5

Preemptions in utility model

task 2

execution window

task 1

uti

lity

Calculate utility accrualReference point?

Which?What happens on preemption?How many?

same utility accrual?

utility accrual

+

_

6

Preemptions in utility model

task 2

execution window

task 1

Calculate utility accrualReference point?

Which?What happens on preemption?How many?

Integral over execution?

uti

lity

utility accrual

+

_

7

Motivating applications

Calculate utility accrualReference point

Multimedia display time dictates video quality

ControlInput/output dictate control performance

Integral over execution???

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Discussion

Utility accrual Applications

Reference point

Integral model

12

Discussion

Utility accrual Applications

Reference point

multimedia and control

Integral model does not ignore

preemption

13

Discussion

Utility accrual Applications

Reference point

can we ignore preemptions?

multimedia and control

Integral model does not ignore

preemption

are there any?

14

Discussion

Utility accrual Applications

Reference point

can we ignore preemptions?

multimedia and control

Integral model does not ignore

preemption

are there any?