Multicore and AUTOSAR

Forschungsseminar Informatik
Multicore and AUTOSAR
05/13/2019 / 261
Presentation START
Hansang Lee
Automotive Software Engineering
13th May 2019

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Contents
▪ Background Knowledge
· What is AUTOSAR ?
· Why AUTOSAR ?
· AUTOSAR Architecture
▪ AUTOSAR-compliant Multicore-systems
· AUTOSAR Architecture with Multi-core
· Why Multi-core is needed ?
· Speedup with Multi-core
· Pros and Cons
▪ Memory Management
· Memory Stack
· Shared Buffer
▪ Scheduling Concept
· Partitioned/Global Scheduling

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Background Knowledge

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What is AUTOSAR? [1] [2]
AUTomotive Open System ARchitecture is a worldwide development partnership of automotive
interested parties founded in 2003. As the automotive electronics
share is being drastically grown up over the past couple decades,
so several automotive industries such as, Bosch, Daimler and
BMW etc. established a development partnership to solve
their facing challenges efficiently and economically.
Nowadays, AUTOSAR is widely used in Europe as the well-
established standard for automobiles. In addition to this, it has
recently been extending its area to Asia(Korea, China, Japan)
and even USA.
▪ The challenges,
> E/E Complexity is growing up fast.
> Software Quantity is exploding.
> Many different hardware platforms are used.
> Development processes and data formats are not
harmonized.
▪ The main objective,
“To improve the quality of software and reduce the cost by re-use”

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Why AUTOSAR? [3]
▪ Software is highly “hardware dependent”
▪ Complexing development process
▪ Not economical
▪ Software is largely “hardware independent”
▪ Simplified development process
▪ High Flexibility and Reusability of software
Introduction
of AUTOSAR
Application Layer
AUTOSAR Runtime Environment
Hardware
AUTOSAR Basic Software
With AUTOSAR
Application Software
Hardware
Without AUTOSAR
Standardized
AUTOSAR
infrastructure

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AUTOSAR Architecture [4] ● Application Layer
software-components which
constitute the simplest form of an
application with certain
functionality. ASW is equivalent to
an application in PCs or devices.
● Runtime Environment
Acts as a middleware between the
application layer and lower layers.
Basically, it manages the inter- and
intra-ECU communication.
● Basic Software Layer
It can be defined as standardized
software module offering various
services. It provides the
infrastructural functionality on
an ECU. BSW is equivalent to the
operating system and drivers in
PCs.
● Hardware
Microcontroller / ECU Hardware
Communication Bus
Gateway

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AUTOSAR-compliant Multicore Systems

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AUTOSAR Architecture with Multi-core [3]
MCU/ECU Hardware
CPU Core IICPU Core I
Software
Component I
AUTOSAR Runtime Environment
MCU Abstraction Layer
Service Layer
ECU Abstraction Layer
Service Layer
Software
Component II
Software
Component III
Software
Component IV
Operating System

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Why Multi-core is needed? [2]
1975-1985 1985-1995 1995-2005 2005-2015
The Growing Number of “Automotive Software”
• Automotive Industries, under Heavy Development-
“ Infotainment ”
“ Vehicle Automation ”
• High Performance Requirements of ECUs
• Increasing Performance by increasing Clock Rate
is obsolete

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Speedup with Multi-core [6] [10]
1
2
3
4
5
6
7
1 2 4 8
Speedup(howmanytimesfaster?)
Number of Processors (Cores)
Gustafson’s Law 90%
80%
70%
60%
50%
40%
30%
20%
10%
Ideal Linear Speedup
Amdahl’s Law
Linear Speedup in reality

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Pros and Cons [5] [7]
Pros
“ Workload/Calculation Distribution ”
“ More Computational Resources ”
“ Reduction of Hardware Costs ”
“ Flexibility of Task Allocation ”
Cons
“ Suitable Software Architecture ”
“ Algorithms for Parallel Computing ”
“ Safety ”
“ Weak Predictability ”

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Memory Management

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Memory Stack [12] [13]
Services Layer
Non-Volatile Memory Manager
(NVM)
Memory Interface (MemIf)
(Memory Abstraction Interface)
Flash Driver
(Fls)
EEPROM Driver
(Eep)
Memory Stack Model
MemoryHardwareAbstractionNVRAMManagerMemoryDrivers
Flash EEPROM
Emulation (Fee)
EEPROM
Abstraction (Ea)

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In AUTOSAR layered-architecture, Memory Stack is
“ A collection of Software Modules and Device Drivers ”
Services Layer
Flash EEPROM
Emulation (Fee)
EEPROM
Abstraction (Ea)
Flash Driver
(Fls)
EEPROM Driver
(Eep)
Memory Stack Model
(NVM)
● Non-Volatile Memory Manager ensures,
“ Data Storage ”
“ Maintenance of Non-Volatile Data ”
“ Management of the Non-Volatile Data of EEPROM / FLASH EEPROM ”
● Memory Interface ensures that,
“ NVM is independent of the driver interface layers of Fee and Eep ”
● EEPROM Abstraction and EEPROM Driver provide,
“ Services for Reading/Writing/Erasing Data to/from an EERPROM ”
● Flash EEPROM Emulation provides NVM with,
“ Virtual Addressing Scheme, Segmentation ”
“ Virtually unlimited number of Erase Cycles ”
● Flash Driver provides,
“ Initialization of Flash Memory ”
“ Services for Reading/Writing to/from Flash Memory ”

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Services Layer
(NVM)
Flash Driver
(Fls)
EEPROM Driver
(Eep)
Memory Stack Model
Flash EEPROM
Emulation (Fee)
EEPROM
Abstraction (Ea)

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Services Layer
(NVM)
Flash EEPROM
Emulation (Fee)
EEPROM
Abstraction (Ea)
Flash Driver
(Fls)
EEPROM Driver
(Eep)
Memory Stack Model

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Services Layer
(NVM)
Flash EEPROM
Emulation (Fee)
EEPROM
Abstraction (Ea)
Flash Driver
(Fls)
EEPROM Driver
(Eep)
Memory Stack Model

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Services Layer
(NVM)
Flash EEPROM
Emulation (Fee)
EEPROM
Abstraction (Ea)
Flash Driver
(Fls)
EEPROM Driver
(Eep)
Memory Stack Model

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Shared Buffers [9]
Invocation of the same service on the different cores with a shared data buffer
Access to “Shared Buffers” must be protected
against “Concurrent Access”

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Shared Buffers without Protection
Core0
Service X
Memory
Core1
Service X
Shared Buffer
Variable : desiredTemperature”
The expected value of
the shared buffer is 10,
but the result is 20
[Same Code]
if (desiredTemperature == 0)
desiredTemperature += 10;
[Same Code]
if (desiredTemperature == 0)
desiredTemperature += 10;

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Scheduling Concept

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Partitioned/Global Scheduling
Two type of “Scheduling Concepts” for “Task Allocation”
● Partitioned Scheduling
“ Once a task has been allocated to a core, it cannot migrate to another one ”
“ This scheduling frameworks basically exists for single-core systems ”
● Global Scheduling
“ Tasks are allowed to fully migrate between different cores ”
“ Global Queue ”
“ Task Scheduler ”
Task6
Task5
Task4
Task3
Task2
… …
CORE 0
CORE 1
When the tasks get ready to execute
Task Scheduler decides which core any task
can/should be allocated to.
Task1
Task2
Global Queue

References I
Wikipedia; AUTOSAR;
“https://en.wikipedia.org/wiki/AUTOSAR”, Last edited on 7 April 2019;
[Online]
[1]
Юрий Сорокин; Introduction to AUTOSAR;
“https://www.youtube.com/watch?v=s_FY0ujP2rA&list=PLh-MKr4shv01vAj59u0b8qrDCUGjIeEzZ&index=6”, 22 Dec 2017;
[Online Video]
[2]
EBAutomotiveSoftware; AUTOSAR 4.0 - A first glance;
“https://www.youtube.com/watch?v=gDAvlw-FYZY&list=PLh-MKr4shv01vAj59u0b8qrDCUGjIeEzZ&index=7”, 24 Oct 2011;
[Online Video]
[3]
Embitel; Decoding the “Component Concept” of the Application Layer in AUTOSAR;
“https://www.embitel.com/blog/embedded-blog/decoding-the-component-concept-of-the-application-layer-in-autosar”, 9 May 2018;
[Online]
[4]
Simon Widlund, Anton Annenkov; Migrating a Single-core AUTOSAR Application to a Multi-core Platform: Challenges, Strategies and Recommendations;
“http://publications.lib.chalmers.se/records/fulltext/250043/250043.pdf”, 2017;
[Master Thesis]
[5]
Wikipedia; Gustafson's law
“https://en.wikipedia.org/wiki/Gustafson%27s_law”, Last edited on 21 February 2019
[Online]
[6]
BMW Car IT GmbH; Multicore on AUTOSAR – from the idea to series production
“http://www.bmw-carit.de/projects/multicore-on-autosar.php”;
[Online]
[7]
AUTOSAR Documentation; Technical Overview V2.2.1 R3.0 Rev 0001;
“https://www.autosar.org/fileadmin/user_upload/standards/classic/3-0/AUTOSAR_TechnicalOverview.pdf”;
[Documentation]
[8]
05/13/2019 / 2623

References II
AUTOSAR Documentation; Guide to Multi-Core Systems V1.1.0 R4.1 Rev3;
“https://www.autosar.org/fileadmin/user_upload/standards/classic/4-1/AUTOSAR_EXP_MultiCoreGuide.pdf”;
[Documentation]
[9]
Wikipedia; Amdahl’s Law;
“https://en.wikipedia.org/wiki/Amdahl%27s_law”,
[Online]
[10]
AUTOSAR Documentation; Specification of Flash EEPROM Emulation V2.0.0 R4.0 Rev3
“https://www.autosar.org/fileadmin/user_upload/standards/classic/4-0/AUTOSAR_SWS_FlashEEPROMEmulation.pdf”,
[Online]
[11]
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Presentation END
05/13/2019 / 2625

Questions & Answers
05/13/2019 / 2626

Multicore and AUTOSAR

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