A Timing Verification Methodology for AUTOSAR Series Development

A Timing Verification Methodology
for AUTOSAR Series Development
Dr. Kai Richter, Dr. Marek Jersak, Symtavision GmbH
Dr. Stefan Voget, Continental Engineering Services GmbH
Dr. Ulrich Freund, ETAS GmbH
Joachim Stroop, dSPACE GmbH
Markus Kühl, aquintos GmbH

Outline
� Motivation
� Timing Verification Techniques and the V-Model
� AUTOSAR Timing Model
� AUTOSAR Flow & Tools
� AUTOSAR Timing Methodology
A Timing Verification Methodology for AUTOSAR Series Development
Dr. Kai Richter, Symtavision GmbH, Germany
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S1
S2
S3
S4
Questions answered by Timing Analysis
R1 ts= 1ms
et= 50µs
R6 ts= 5ms
et= 180µs
R2 ts= 1ms
et= 180µs
R8 ts= 5ms
et= 140us
R9 ts= 5ms
et= 360µs
R4 ts= 5ms
et= 130µs
R3 ts= 1ms
et= 110µs
R5 ts= 5ms
et= 870µs
Sensors Actuators
Software Components Event Chains:
SW-C1 = {R1, R2, R3, R4, R5} EC1 = S1�R1�R2�R3�A1
SW-C2 = {R6, R7}
EC2 = S2�R1�R2�R3�R7�A2
SW-C3 = {R8, R9}
EC3 = S2�R1�R8�R4�R5�R7�A2
One Software Architecture
R7 ts= 2.5ms
et= 75µs
A1
A2
A3
ECU Configuration 1 � Deadline miss + Overload
ECU Configuration 2 � Deadline OK
+ Performance Reserves + Safety Proof
AUTOSAR lets you specify SW architecture & ECU configuration !
Timing Analysis lets you distinguish good from bad designs !
A Timing Verification Methodology for AUTOSAR Series Development
Dr. Kai Richter, Symtavision GmbH, Germany
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Timing Verification Techniques and Flows
SW Archi
Timing Constraints
ECU Config
Timing Constraints
Integration
Comparisons
Timing Constraints
ECU
model-based
techniques
Trace
Scheduling Analysis
Timing Model
measurement-based
techniques
A Timing Verification Methodology for AUTOSAR Series Development
Dr. Kai Richter, Symtavision GmbH, Germany
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Timing Verification Early and Late
SW Archi
Budgets
Estimates
ECU Config
Integration
Prototype
Scheduling Analysis
Timing Model
Trace
SW Archi
Scheduling Analysis
Timing Model
ECU Config
Integration
Trace
A-D Sample
Scheduling Analysis
Timing Model
Trace
Scheduling Analysis
Timing Model
Target ECU
A Timing Verification Methodology for AUTOSAR Series Development
Dr. Kai Richter, Symtavision GmbH, Germany
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Timing Model in AUTOSAR
� AUTOSAR 3.2
� System: SW architecture
� OS config: tasks, schedule table, offsets, ...
� RTE config: runnable mapping, position in task, ...
� SW Module Description: runnable / task execution times
� AUTOSAR 4.0 Timing Extension
� timing constraints, requirements, and budgets
� event chains (for end-to-end constraints)
� event triggerings (for capturing dynamic behavior)
A Timing Verification Methodology for AUTOSAR Series Development
Dr. Kai Richter, Symtavision GmbH, Germany
6

Timing Event Chains
� signal path through application
� defined by stimulus and end event
� can be constrained (min, max, nominal)
� can be segmented (sub chains)
S1
S2
S3
S4
R1 ts= 1ms
et= 50µs
R6 ts= 5ms
et= 180µs
R2 ts= 1ms
et= 180µs
R8 ts= 5ms
et= 140us
R9 ts= 5ms
et= 360µs
A Timing Verification Methodology for AUTOSAR Series Development
Dr. Kai Richter, Symtavision GmbH, Germany
R4 ts= 5ms
et= 130µs
R3 ts= 1ms
et= 110µs
R5 ts= 5ms
et= 870µs
R7 ts= 2.5ms
et= 75µs
Stimulus Response
Segments
A1
A2
A3
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Event Triggering Constraints
� capture dynamic timing behavior of event occurrences
� external signals (sensors, buttons, etc.)
� interrupts
� etc.
� 5 basic models:
� periodic
� sporadic
� burst
� concrete
� arbitrary
� each with model-specific parameters, e.g. period, jitter, min/max
interarrival, offset, occurrence, etc.
A Timing Verification Methodology for AUTOSAR Series Development
Dr. Kai Richter, Symtavision GmbH, Germany
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ECU Timing Design
SW
architecture
CPU
selection
Execution time
budget optimization
Load Analysis
n y
OK?
Schedule concept
optimization
execution times (from prototype trace)
execution time budgets, estimates
(from planing and negotiation)
Virtual
Schedule
n y
OK?
ECU configuration
optimization
Event Chain
Verification
n y
OK?
ECU Configuration
OK
A Timing Verification Methodology for AUTOSAR Series Development
Dr. Kai Richter, Symtavision GmbH, Germany
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ECU Tooling Example: SystemDesk & SymTA/S
SystemDesk
ECU Configuration
OK
SW
architecture
proceed with
RTE generation ...
SymTA/S
Load Analysis
Virtual
Schedule
execution times
Event Chain
Verification
Budgets
Estimates
Prototype Traces
timing report:
• load
• schedule
• event chains
comparison of configuration alternatives:
optimization of RTE (runnable-mapping)
and OS (task offsets)
A Timing Verification Methodology for AUTOSAR Series Development
Dr. Kai Richter, Symtavision GmbH, Germany
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E/E and Network Tooling Example: PREEvision & SymTA/S
taken from: In search of the best migration strategy from CAN to FlexRay. FlexRay Product Day 2009. DAIMLER, aquintos, Symtavision
A Timing Verification Methodology for AUTOSAR Series Development
Dr. Kai Richter, Symtavision GmbH, Germany
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General Tool Integration Aspects
� AUTOSAR XML: standardized file-based configuration exchange
� ARTOP: optional Eclipse plug-in of base methods for AUTOSAR tools
Tool 2 Tool 1
Tool 3
Tool 4
Tool 5
Eclipse Eclipse
Eclipse
.XML
A Timing Verification Methodology for AUTOSAR Series Development
Dr. Kai Richter, Symtavision GmbH, Germany
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AUTOSAR Timing Methodology
SW Archi
Budgets
Estimates
ECU Config
Integration
Prototype
Scheduling Analysis
Timing Design
Trace
SW Archi
Scheduling Analysis
ECU Config
Timing Model
Integration
Trace
A-D Sample
Scheduling Analysis
Trace
Scheduling Analysis
Timing Model Timing Model
Timing Model
Continuous
Timing Analysis
Timing Model
Timing Verification
Target ECU
A Timing Verification Methodology for AUTOSAR Series Development
Dr. Kai Richter, Symtavision GmbH, Germany
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