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Swiss FederalInstitute of Technology
Computer Engineeringand Networks Laboratory
Modular Performance Analysis
with Real-Time Calculus
Lothar Thiele, Simon Künzli, Alex Maxiaguine, Ernesto Wandeler, et al.
Computer Engineering and Networks Laboratory
ETH Zurich, Switzerland
23. November 2005
Workshop on Distributed Embedded Systems, Leiden, The Netherlands
2Swiss FederalInstitute of Technology
Computer Engineeringand Networks Laboratory
Real-Time Calculus
• Developed at ETH Zurich since 2000
• Based on:– Max-Plus/Min-Plus Algebra [Quadrat et al.,
1992]– Network Calculus [Le Boudec & Thiran, 2001]
3Swiss FederalInstitute of Technology
Computer Engineeringand Networks Laboratory
Abstract Models for Performance Analysis
ProcessorTask
InputStream
ServiceModel
LoadModel
Concrete Instance
Abstract Representation
Task / ProcessingModel
4Swiss FederalInstitute of Technology
Computer Engineeringand Networks Laboratory
Load Model
t [ms]
eventsEvent Stream
maximum / minimum arriving demand in anyinterval of length 2.5 ms
2.5
Arrival Curve & Delay ddemand
[ms] 2.5
number of events in in t=[0 .. 2.5] ms
deadline = d
ServiceModel
LoadModel
ProcessingModel
l
u
5Swiss FederalInstitute of Technology
Computer Engineeringand Networks Laboratory
Load Model - Examples
periodic periodic w/ jitter
periodic w/ burst complex
ServiceModel
LoadModel
ProcessingModel
6Swiss FederalInstitute of Technology
Computer Engineeringand Networks Laboratory
Service Model
t [ms]
availabilityResource Availability
maximum/minimum available service in anyinterval of length 2.5 ms
available service in t=[0 .. 2.5] ms
2.5
u
l
Service Curves [l, u]service
[ms] 2.5
ServiceModel
LoadModel
ProcessingModel
7Swiss FederalInstitute of Technology
Computer Engineeringand Networks Laboratory
Service Model - Examples
full resource bounded delay
TDMA resource periodic resource
ServiceModel
LoadModel
ProcessingModel
8Swiss FederalInstitute of Technology
Computer Engineeringand Networks Laboratory
d
Task / Processing Model
RTC
’
’
ServiceModel
LoadModel
ProcessingModel
Real-Time CalculusReal-Time Calculus
9Swiss FederalInstitute of Technology
Computer Engineeringand Networks Laboratory
Scheduling / ArbitrationFP
GPS
EDF
TDMA
10Swiss FederalInstitute of Technology
Computer Engineeringand Networks Laboratory
Analysis: Delay and Backlog
delay dmax
backlog bmax
l
u[l, u]
[l, u]
[l’, u’]
[l’, u’]
RTC
ServiceModel
LoadModel
ProcessingModel
11Swiss FederalInstitute of Technology
Computer Engineeringand Networks Laboratory
Case Study
ECU1
BUS
CC1
ECU2CC2
ECU3CC3
S1
S2
S3
S4
S5
5 Real-Time Input Streams- with jitter- with bursts- deadline > period
3 ECU’s with own CC’s
12 Tasks & 7 Messages- with different WCED
2 Scheduling Policies- Earliest Deadline First (ECU’s)- Fixed Priority (ECU’s & CC’s)
Hierarchical Scheduling- Static & Dynamic Polling Servers
Bus with TDMA- 4 time slots with different lengths (#1,#3 for CC1, #2 for CC3, #4 for CC3)
Total Utilization:- ECU1 59 %- ECU2 87 %- ECU3 67 %- BUS 56 %
12Swiss FederalInstitute of Technology
Computer Engineeringand Networks Laboratory
Specification Data
13Swiss FederalInstitute of Technology
Computer Engineeringand Networks Laboratory
The Distributed Embedded System...
ECU1 BUS(TDMA)
C1.1
C1.2
C2.1
C3.1
C4.1
C5.1
C3.2
T1.1
T1.3T2.1
T3.1
T3.3
PS
FPFP
CC1
ECU2
T4.1
T5.1
FP
CC2
ECU3
T1.2
FP FP
CC3
T3.2
FP
EDF
T2.2
PS
T4.2
PS
T5.2
S1
S2
S3
S4
S5
S1
S3
14Swiss FederalInstitute of Technology
Computer Engineeringand Networks Laboratory
... and its Real-Time Calculus Model
S5
S4
S1
S2
S3
T1.1
T1.3
C4.1
C5.1
TDMA
CPU
T2.1
T3.1
T3.3
CPU
T4.1
T5.1
CPU
PS
T1.2
EDF
PS
T3.2
C1.2
C3.2
C2.1
C3.1
C1.1
T5.2
T4.2
T2.2
PS
ECU1
ECU2
ECU3BUS
CC1
CC2
CC3
15Swiss FederalInstitute of Technology
Computer Engineeringand Networks Laboratory
Input & Output of Stream 3
S5
S4
S1
S2
S3
T1.1
T1.3
C4.1
C5.1
TDMA
CPU
T2.1
T3.1
T3.3
CPU
T4.1
T5.1
CPU
PS
T1.2
EDF
PS
T3.2
C1.2
C3.2
C2.1
C3.1
C1.1
T5.2
T4.2
T2.2
PS
ECU1
ECU2
ECU3BUS
CC1
CC2
CC3
16Swiss FederalInstitute of Technology
Computer Engineeringand Networks Laboratory
Service Demand & Supply for EDF Block
S5
S4
S1
S2
S3
T1.1
T1.3
C4.1
C5.1
TDMA
CPU
T2.1
T3.1
T3.3
CPU
T4.1
T5.1
CPU
PS
T1.2
EDF
PS
T3.2
C1.2
C3.2
C2.1
C3.1
C1.1
T5.2
T4.2
T2.2
PS
ECU1
ECU2
ECU3BUS
CC1
CC2
CC3
17Swiss FederalInstitute of Technology
Computer Engineeringand Networks Laboratory
Service Demand & Supply for EDF Block
S5
S4
S1
S2
S3
T1.1
T1.3
C4.1
C5.1
TDMA
CPU
T2.1
T3.1
T3.3
CPU
T4.1
T5.1
CPU
PS
T1.2
EDF
PS
T3.2
C1.2
C3.2
C2.1
C3.1
C1.1
T5.2
T4.2
T2.2
PS
ECU1
ECU2
ECU3BUS
CC1
CC2
CC3
18Swiss FederalInstitute of Technology
Computer Engineeringand Networks Laboratory
Service Demand & Supply for EDF Block
S5
S4
S1
S2
S3
T1.1
T1.3
C4.1
C5.1
TDMA
CPU
T2.1
T3.1
T3.3
CPU
T4.1
T5.1
CPU
PS
T1.2
EDF
PS
T3.2
C1.2
C3.2
C2.1
C3.1
C1.1
T5.2
T4.2
T2.2
PS
ECU1
ECU2
ECU3BUS
CC1
CC2
CC3
19Swiss FederalInstitute of Technology
Computer Engineeringand Networks Laboratory
Buffer Requirements
S5
S4
S1
S2
S3
T1.1
T1.3
C4.1
C5.1
TDMA
CPU
T2.1
T3.1
T3.3
CPU
T4.1
T5.1
CPU
PS
T1.2
EDF
PS
T3.2
C1.2
C3.2
C2.1
C3.1
C1.1
T5.2
T4.2
T2.2
PS
ECU1
ECU2
ECU3BUS
CC1
CC2
CC3
3
3
1.81
5
2
2 5
4
6
5 4.1
1 5
1.3 4.5
20Swiss FederalInstitute of Technology
Computer Engineeringand Networks Laboratory
Delay Guarantees
S5
S4
S1
S2
S3
T1.1
T1.3
C4.1
C5.1
TDMA
CPU
T2.1
T3.1
T3.3
CPU
T4.1
T5.1
CPU
PS
T1.2
EDF
PS
T3.2
C1.2
C3.2
C2.1
C3.1
C1.1
T5.2
T4.2
T2.2
PS
ECU1
ECU2
ECU3BUS
CC1
CC2
CC3
4910
4550
87
125
550
303
329
2140
21Swiss FederalInstitute of Technology
Computer Engineeringand Networks Laboratory
System Analysis Time
• Pentium Mobile 1.6GHz
• Matlab 7
• RTC Kernel Prototype (Java 1.4)
22Swiss FederalInstitute of Technology
Computer Engineeringand Networks Laboratory
Tool Support
• Matlab Toolbox for Real-Time Calculus– Version 1.0 to be released December 2005
• Simulink Frontend– Prototype under
development
23Swiss FederalInstitute of Technology
Computer Engineeringand Networks Laboratory
Limitations of Real-Time Calculus
• High Level of Abstraction
• Time-Interval Domain
Swiss FederalInstitute of Technology
Computer Engineeringand Networks Laboratory
Thank you!
Ernesto Wandeler