Oplægget blev holdt ved et seminar i InfinIT-interessegruppen Højniveausprog til indlejrede systemer den 12. marts 2014. Læs mere om interessegruppen her: http://infinit.dk/dk/interessegrupper/hoejniveau_sprog_til_indlejrede_systemer/hoejniveau_sprog_til_indlejrede_systemer.htm

1. Schedulability analysis using Uppaal
and Uppaal SMC in CRAFTERS
Abdeldjalil Boudjadar,
Alexandre David,
Jin Hyun Kim,
Kim G. Larsen,
Marius Mikuˇcionis,
Ulrik Nyman,
Arne Skou
InfinIT Talk 12th of March 2014

2. CRAFTERS project
Title ConstRaint and Application driven Framework
for Tailoring Embedded Real-time Systems.
Period Jun 2012 - May 2015
Website www.crafters-project.org
People Two Post Docs @AAU
Partners 25

3. CRAFTERS project
Goals As direct effects of the project results
30% reduction of the total cost of ownership,
50% shorter time-to-market, and
30% decrease of the number of development
assets are expected.

4. AAU contributions
Deliverables
• Model transformations (UML -> Uppaal)
• Real-time testing tool, Uppaal TRON
Research
• New research on schedulability analysis

5. Publications
FACS 2013 Hierarchical Scheduling Framework Based on
Compositional Analysis Using Uppaal
(Published)
ERTS2
2014 Schedulability and Energy Efficiency for
Multi-core Hierarchical Scheduling Systems
(Published)
Submitted1 Statistical Model Checking for Improved
Resource Utilization in Hierarchical Scheduling
Systems
Submitted2 Degree of Schedulability of Mixed-Criticality
Real-time Systems with Probability-based
Sporadic Tasks

6. A hierarchical scheduling system
System
Component1 Component2
task1 task2 task3 task4 task5
RM
(100,37)
EDF
EDF
(70,25)
(250,40) (400,50) (140,7) (150,7) (300,30)
Figure: Example of hierarchical scheduling system.

7. Schedulability analysis
?? Do you use hierarchical scheduling?
?? How do you perform schedulability analysis?
Motivation Separation of concerns. ReComp.

8. Schedulability analysis
sbfΓ(t) =
t − (Π − Θ)
Π
· Θ + s (1)
where
s = max t − 2(Π − Θ) − Π
t − (Π − Θ)
Π
, 0 . (2)

9. FACS 2013
System
EDF
Component1 Component2
task1 task2 task3 task4
EDF,.RM:.scheduling.policies..A,.A1,.A2:.analysis.processes.
A
A1 A2
task5
EDF RM
Figure: Compositional analysis.

10. Submitted1
∀t ∈ ]0; 2 · LCMW ] : dbfW (t) ≤ sbfΓ(t) (3)

11. FACS 2013
supplying_time[supid]'==0
&& curTime <= sup[supid].prd
- sup[supid].budget
+ supplying_time[supid]
&& curTime <= sup[supid].prd
stop_supplying[supid]!
replenishment[supid]!
supplying_time[supid]'==1
&& supplying_time[supid]<=sup[supid].budget
curTime <=sup[supid].prd
&& supplying_time[supid]'==0
NotSupplying
curTime ==sup[supid].prd
curTime < sup[supid].prd -sup[supid].budget + supplying_time[supid]
stop_supplying[supid]!
supplying_time[supid]>=sup[supid].budget
start_supplying[supid]!
supplying_time[supid]<=sup[supid].budget
supplying[supid]=1
Supplying
supplying[supid]=1
supplying[supid]=0
Done
supplying[supid]=0
curTime=0, supplying_time[supid]=0,
supplying[supid]=0
Figure: Non-deterministic supplier template

12. FACS 2013
Listing 1: Data structure for timed action
const cmd_set_t Target_tracking = {
{ INPUT , 3, 110, 122, 0},
{ INPUT , 3, 164, 182, 0},
{ INPUT , 3, 100, 122, 0},
{ INPUT , 3, 146, 162, 0},
{ COMPUTE , 0, 3600, 4000, 0},
{ OUTPUT , 3, 200, 222, 0},
{ OUTPUT , 3, 146, 162, 0},
FIN ,FIN ,FIN ,FIN ,FIN
};
const cmd_set_t Target_sweetening = {
{ INPUT , 3, 110, 122, 0},
{ COMPUTE , 0, 1800, 2000, 0},
FIN ,FIN ,FIN ,FIN ,FIN ,FIN ,FIN ,FIN ,FIN ,FIN
};

13. ERTS2
2014: Vision
Schedulability
requirements
Energy
consumption
Hierarchical
system architecture
L _
_
_
T2
S
C1 C2
T1 T3 T4
UPPAAL Network of
Parameterized
Stopwatch Automata
Schedulability
analysis
(model
checking)
Energy efficiency
(Stochastic model
checking)
SMC
Schedulable:
yes / no
Energy
profile
Concretetaskbehavior
Concretetaskbehavior
CPU1 CPU2
Figure: Overview of the analysis framework

14. ERTS2
2014: Vision
Schedulability
requirements
Energy
consumption
Hierarchical
system architecture
L _
_
_
T2
S
C1 C2
T1 T3 T4
UPPAAL Network of
Parameterized
Stopwatch Automata
Schedulability
analysis
(model
checking)
Energy efficiency
(Stochastic model
checking)
SMC
Schedulable:
yes / no
Energy
profile
Concretetaskbehavior
Concretetaskbehavior
CPU1 CPU2
Figure: Overview of the analysis framework

15. ERTS2
2014: Case study
Avionics
Hard-Subsystem
( 25, insuf, EDF)
Controls and Display
(20, 15, FP )
Targeting
(40, 23, FP)
Navigation
(30, 11, EDF)
Weapon Ctrl.
(10, 8, FP)
HUD Display
T9(50,6,50)
MPD Display
T10(50,8,50)
MPD Button Resp.
T11(200,1,200)
Change Display
T12 (200,1,200)
Flight Data
T1(50,8,50)
Steering
T2(80,6,80)
Target Tracking
T3(40,4,40)
Target Sweetening
T4(40,2,40)
AUTO/CCIP Toggle
T5(200,1,200)
Weapon Release
T8(10,1,5)
Weapon Trajectory
T6 (100,7,100)
Reinitiate Trajectory
T7(400,6,400)
insuf : insufficient budget
Figure: Architecture of the hierarchical scheduling system

16. ERTS2
2014: Cumulated energy
consumption
Energy Consumption
Task 2 Execution
Task 1 Execution
time
value
0
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
0 30 60 90 120 150 180 210 240 270 300 330 360 390 420 450 480 510 540 570 600 630 660 690
Simulations (1)
Figure: Cumulated energy consumption for two individual tasks

17. ERTS2
2014: Energy profile
Figure: Energy profile for two tasks, 1000 runs, 1000000 time units

18. Submitted1
Submitted1 Statistical Model Checking for Improved
Resource Utilization in Hierarchical Scheduling
Systems
• Comparison with conventional method.
• Discovered error in conventional tool CARTS.
Confirmed by tool makers.

19. Comparison of schedulability analysis of
CARTS and Uppaal models
Comp Tasks P, WCET
CARTS SMC
EDF RM EDF RM
S1
T1 500, 30
100, 32.5 100, 32.5 100, 33 100, 33
T2 500, 100
S2
T1 170, 30
100, 46.67 100, 47.5 100, 46 100, 48
T2 500, 100
S3
T1 250, 40
150, 42.5 150, 42.5 150, 45 150, 45
T2 750, 50
S4
T1 80000, 6890
50000, 15082 50000, 15082 50000, 15082 50000, 15082
T2 100000, 8192
T3 200000, 2644
10000, 1880 10000, 2155.6 10000, 1875 10000, 2155
T4 1000000, 5874

20. Task synchronization

21. Submitted2
Submitted2 Degree of Schedulability of Mixed-Criticality
Real-time Systems with Probability-based
Sporadic Tasks
• Mixed criticality
• Sporadic tasks
• Simulation

22. Sporadic task and events

23. Event patterns

24. Missing deadlines
Figure: Execution of a sporadic task

25. PoMD
Definition (Percentage of Missed Deadlines)
The PoMD of an entity X for a run π is given by:
PoMDX
(π) = (lim sup
t→∞
Misst (X, π)
Trigt (X, π)
) × 100

26. DoQoS
Definition (Degradation of Quality of Service)
The DoQoS of a task Ti over a finite set of runs Π is defined
as:
DoQoSTi
(Π) =
0 if limt→∞ π∈Π Misst (Ti, π) = 0
limt→∞
π∈Π Overrunt (Ti ,π)
π∈Π Misst (Ti ,π) Otherwise

27. Sched◦
Definition (The degree of schedulability )
We define the Sched◦
of an entity in terms of two factors
Sched◦
P and Sched◦
D to be given by:
Sched◦
P =
∞ if PoMD = 0
1
PoMD Otherwise
Sched◦
D =
∞ if DoQoS = 0
1
DoQoS Otherwise

28. Sufficient budget
Table: The degree of schedulability of tasks under periodic
events
Component ((40, 23), FPS) PoMD DoQoS
Tp
3 (40, 4), 0 0
Ts
4(40, 2), 0 0

29. Case study
Avionics
Hard-Subsystem
( 25, insuf, EDF)
Controls and Display
(20, 15, FP )
Targeting
(40, 23, FP)
Navigation
(30, 11, EDF)
Weapon Ctrl.
(10, 8, FP)
HUD Display
T9(50,6,50)
MPD Display
T10(50,8,50)
MPD Button Resp.
T11(200,1,200)
Change Display
T12 (200,1,200)
Flight Data
T1(50,8,50)
Steering
T2(80,6,80)
Target Tracking
T3(40,4,40)
Target Sweetening
T4(40,2,40)
AUTO/CCIP Toggle
T5(200,1,200)
Weapon Release
T8(10,1,5)
Weapon Trajectory
T6 (100,7,100)
Reinitiate Trajectory
T7(400,6,400)
insuf : insufficient budget
Figure: Architecture of the hierarchical scheduling system

30. Generic Avionics Components and Tasks
Component Criticality Ti ei pi di Importance
Navigation
Hard Aircraft flight data(Tp
1
) 8 50(55) critical
critical Steering(Tp
2
) 6 80 critical
Targeting
Hard Target tracking(Tp
3
) 4 40 critical
critical Target sweetening(Ts
4) 2 40 critical
AUTO/CCIP toggle(Ts
5) 1 200 critical
Weapon Hard Weapon trajectory(Tp
6
) 7 100 critical
Control non-critical Reinitiate trajectory(Ts
7) 6 400 essential
Weapon release(Tp
8
) 1 10 5 critical
Soft
HUD display(Tp
9
) 6 55(52) essential
Controls & MPD tactical display(Tp
10
) 8 50(52) essential
Displays MPD button response (Ts
11) 1 200 background
Change display mode (Ts
12) 1 200 background

31. Schedulability degree of component
Controls & Displays
Task Sched◦
Budget=14 Budget=17 Budget=19 Budget=20
HUD Display(T9)
DoQoS 0.004±0.003 0 0 0
PoMD 0.004±0.004 0 0 0
MPD Display(T10)
DoQoS 3.068±0.151 0.343±0.052 0.003±0.003 0
PoMD 0.231±0.018 0.002±0.002 0.0005±0 0
MPD Button(T11)
DoQoS 0 0 0 0
PoMD 0 0 0 0
Change Mode(T12)
DoQoS 0 0 0 0
PoMD 0 0 0 0

32. ERTS2
2014: Vision
Schedulability
requirements
Energy
consumption
Hierarchical
system architecture
L _
_
_
T2
S
C1 C2
T1 T3 T4
UPPAAL Network of
Parameterized
Stopwatch Automata
Schedulability
analysis
(model
checking)
Energy efficiency
(Stochastic model
checking)
SMC
Schedulable:
yes / no
Energy
profile
Concretetaskbehavior
Concretetaskbehavior
CPU1 CPU2
Figure: Overview of the analysis framework