Real-Time Scheduling Author: Peter van der Stok CTT-DRTS-WS - - PowerPoint PPT Presentation

▶

Feb 11, 2024 148 likes •392 views

1 Real-Time Scheduling Real-Time Scheduling Author: Peter van der Stok CTT-DRTS-WS Scheduling dd 5-1-2001 Phi l i ps Res ear ch 2 Real-Time Scheduling Overview Three examples water vessel avionics multimedia

SLIDE 1

Phi l i ps Res ear ch

1 Real-Time Scheduling

CTT-DRTS-WS Scheduling dd 5-1-2001

Real-Time Scheduling

Author: Peter van der Stok

SLIDE 2

2 Real-Time Scheduling

Overview

Three examples

– water vessel – avionics – multimedia streaming

SLIDE 3

3 Real-Time Scheduling

Example of RT system: Problem

Water vessel problem

– Requirements

Water should not overflow
Pump should not run dry

– Properties:

Positive but limited influx of water when pump is off
Positive but limited outflux of water when pump is on
Sensors are placed ∆ h from critical levels
d time units needed for level change ∆ h

pump water high sensor -- o water low sensor --o ∆ h ∆ h

SLIDE 4

4 Real-Time Scheduling

Example of RT system: Solution

– Critical conditions should not exist longer than d without response

critical conditions C: water above/below sensor

– Periodic task is released with period T and satisfy deadline D within this period.

If water at low sensor: Task stops pump
If water at high sensor: Task starts pump

– Schedulability conditions: T + D < d

If the task finishes within the period (D = T ) :

2.T < d

T D d ¬ C C t

SLIDE 5

5 Real-Time Scheduling

SLIDE 6

6 Real-Time Scheduling

Avionics functions

Control and check airplane

– Navigation – Communication – Recording – Steering

Specific requirements for IMA

– auto check – maintenance checks

cost effective !!

– reliable

one hour < 10-9
last fault to maintenance > 200h

SLIDE 7

7 Real-Time Scheduling

SLIDE 8

8 Real-Time Scheduling

LRM: line replacable modules

SLIDE 9

9 Real-Time Scheduling

SLIDE 10

10 Real-Time Scheduling

SLIDE 11

11 Real-Time Scheduling

SLIDE 12

12 Real-Time Scheduling

SLIDE 13

13 Real-Time Scheduling

SLIDE 14

14 Real-Time Scheduling

SLIDE 15

15 Real-Time Scheduling

Video streaming over network into terminal

SLIDE 16

16 Real-Time Scheduling

Terminology Stream Composite stream Task Buffer User application Terminal application

SLIDE 17

17 Real-Time Scheduling

enc. hw scaler enc. disk : non-scalable dmux audio dec. dec. sharp enh. main: scalabale DVD mixer mixer : non-scalable scaler digitizer: non-scalable digit audio rend read writer dec enc. scalable task task hierarchical task connection to HW IO buffer data transfer pip: scalable

SLIDE 18

18 Real-Time Scheduling

Application mode Mode parameters Stream modes Application graph

SLIDE 19

19 Real-Time Scheduling

Load changes in MPEG decoding

time load structural load running average temporal load

SLIDE 20

20 Real-Time Scheduling

Control architecture in terminal

1a 1b 2a 2b 3a 3b 4a 4b 5a 5b 5c 6 Set up session Monitor / Alarm / Notify event Select and Set mode Monitor / Alarm / Notify event Set mode and quality level Monitor / Alarm / Notify event Set local parameters Monitor Alarm / Notify event Select and Set resource contract Monitor resource usage Monitor resource usage Resource usage Application Manager RCE control RCE operation Quality Manager Contract-based Resource Manager 1a 3a 2a 4a 1b 2b 5b 3b 5a 4b 5c Mode Manager

SLIDE 21

21 Real-Time Scheduling

Layered view of Integrated framework Network and terminal

Application Manager Mode Manager Terminal QM Subnet QM Terminal RM RCE Subnet RM NCE Terminal Subnet

SLIDE 22

22 Real-Time Scheduling

Terminal T1

Application A2

RCE A2 dmux audio dec. dec. sharp enh. mixer audio rend tuner

Subnet S1 Terminal T2

rend scaler digit RCE A3

SLIDE 23

23 Real-Time Scheduling

Terminal T2 Subnet S1 Terminal T1

RCE A2 dmux audio dec. dec. sharp enh. mixer audio rend tuner router digit RCE A3,1 RCE A3, 1 router scaler

Stream transfer

NCE A3