| 21. |
- Becker, Matthias, 1986-, et al.
(författare)
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A Generic Framework Facilitating Early Analysis of Data Propagation Delays in Multi-Rate Systems
- 2017
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Ingår i: The 23th IEEE International Conference on Embedded and Real-Time Computing Systems and Applications RTCSA'17.
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Konferensbidrag (refereegranskat)abstract
- A majority of multi-rate real-time systems are constrained by a multitude of timing requirements, in addition to the traditional deadlines on well-studied response times. This means, the timing predictability of these systems not only depends on the schedulability of certain task sets but also on the timely propagation of data through the chains of tasks from sensors to actuators. In the automotive industry, four different timing constraints corresponding to various data propagation delays are commonly specified on the systems. This paper identifies and addresses the source of pessimism as well as optimism in the calculations for one such delay, namely the reaction delay, in the state-of-the-art analysis that is already implemented in several industrial tools. Furthermore, a generic framework is proposed to compute all the four end-to-end data propagation delays, complying with the established delay semantics, in a scheduler and hardware-agnostic manner. This allows analysis of the system models already at early development phases, where limited system information is present. The paper further introduces mechanisms to generate job-level dependencies, a partial ordering of jobs, which need to be satisfied by any execution platform in order to meet the data propagation timing requirements. The job-level dependencies are first added to all task chains of the system and then reduced to its minimum required set such that the job order is not affected. Moreover, a necessary schedulability test is provided, allowing for varying the number of CPUs. The experimental evaluations demonstrate the tightness in the reaction delay with the proposed framework as compared to the existing state-of-the-art and practice solutions.
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| 22. |
- Becker, Matthias, 1986-, et al.
(författare)
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A Many-Core based Execution Framework for IEC 61131-3
- 2015
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Ingår i: IECON 2015 - 41st Annual Conference of the IEEE Industrial Electronics Society. ; , s. 4525-4530
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Konferensbidrag (refereegranskat)abstract
- Programmable logic controllers are widely used for the control of automationsystems. The standard IEC 61131-3 defines the execution model as well as theprogramming languages for such systems. Nowadays, actuators and sensorsconnect to the programmable logic controller via automation buses. While suchbuses, as well as the sensors and actuators, become more and more powerful, ashift away from the current distributed operation of automation systems, closeto the field level, becomes possible. Instead, execution of complex controlfunctions can be relocated to more powerful hardware, and technologies. Thispaper presents an execution framework for IEC 61131-3, based on a many-coreprocessors. The presented execution model exploits the characteristics of theIEC 61131-3 applications as well as the characteristics of the many-core processor,yielding a predictable execution. We present the platform architectureand an algorithm to allocate a number of IEC 61131-3 conform applications.Experimental as well as simulation based evaluation is provided.
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| 23. |
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| 24. |
- Becker, Matthias, et al.
(författare)
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Analyzing End-to-End Delays in Automotive Systems at Various Levels of Timing Information
- 2016
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Ingår i: IEEE 4th International Workshop on Real-Time Computing and Distributed systems in Emerging Applications REACTION'16. - Porto, Portugal.
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Konferensbidrag (refereegranskat)abstract
- Software design for automotive systems is highly complex due to the presence of strict data age constraints for event chains in addition to task specific requirements. These age constraints define the maximum time for the propagation of data through an event chain consisting of independently triggered tasks. Tasks in event chains can have different periods, introducing over- and under-sampling effects, which additionally aggravates their timing analysis. Furthermore, different functionality in these systems, is developed by different suppliers before the final system integration on the ECU. The software itself is developed in a hardware agnostic manner and this uncertainty and limited information at the early design phases may not allow effective analysis of end-to-end delays during that phase. In this paper, we present a method to compute end-to-end delays given the information available in the design phases, thereby enabling timing analysis throughout the development process. The presented methods are evaluated with extensive experiments where the decreasing pessimism with increasing system information is shown.
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| 25. |
- Becker, Matthias, 1986-, et al.
(författare)
-
Analyzing end-to-end delays in automotive systems at various levels of timing information
- 2017
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Ingår i: ACM SIGBED Review. - : Association for Computing Machinery (ACM). - 1551-3688. ; 14:4, s. 8-13
-
Tidskriftsartikel (refereegranskat)abstract
- Software design for automotive systems is highly complex due to the presence of strict data age constraints for event chains in addition to task specific requirements. These age constraints define the maximum time for the propagation of data through an event chain consisting of independently triggered tasks. Tasks in event chains can have different periods, introducing over- and under-sampling effects, which additionally aggravates their timing analysis. Furthermore, different functionality in these systems, is developed by different suppliers before the final system integration on the ECU. The software itself is developed in a hardware agnostic manner and this uncertainty and limited information at the early design phases may not allow effective analysis of end-to-end delays during that phase. In this paper, we present a method to compute end-to-end delays given the information available in the design phases, thereby enabling timing analysis throughout the development process. The presented methods are evaluated with extensive experiments where the decreasing pessimism with increasing system information is shown.
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| 26. |
- Becker, Matthias, 1986-
(författare)
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Efficient Resource Management for Many-Core based Industrial Real-Time Systems
- 2015
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Licentiatavhandling (övrigt vetenskapligt/konstnärligt)abstract
- The increased complexity of today’s industrial embedded systems stands inneed for more computational power while most systems must adhere to a restrictedenergy consumption, either to prolong the battery lifetime or to reduceoperational costs. The many-core processor is therefore a natural fit. Due tothe simple architecture of the compute cores, and therefore their good analyzability,such processors are additionally well suited for real-time applications.In our research, we focus on two particular problems which need to be addressedin order to pave the way into the many-core era. The first area is powerand thermal aware execution frameworks, where we present different energyaware extensions to well known load balancing algorithms, allowing them todynamically scale the number of active cores depending on their workload.In contrast, an additional framework is presented which balances workloadsto minimize temperature gradients on the die. The second line of works focuseson industrial standards in the face of massively parallel platforms, wherewe address the automotive and automation domain. We present an executionframework for IEC 61131-3 applications, allowing the consolidation of severalIEC 61131-3 applications on the same platform. Additionally, we discussseveral architectural options for the AUTOSAR software architecture on suchmassively parallel platforms.
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| 27. |
- Becker, Matthias, 1986-, et al.
(författare)
-
End-to-End Timing Analysis of Cause-Effect Chains in Automotive Embedded Systems
- 2017
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Ingår i: Journal of systems architecture. - : Elsevier BV. - 1383-7621 .- 1873-6165. ; 80:Supplement C, s. 104-113
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Tidskriftsartikel (refereegranskat)abstract
- Automotive embedded systems are subjected to stringent timing requirements that need to be verified. One of the most complex timing requirement in these systems is the data age constraint. This constraint is specified on cause- effect chains and restricts the maximum time for the propagation of data through the chain. Tasks in a cause-effect chain can have different activation patterns and different periods, that introduce over- and under-sampling effects, which additionally aggravate the end-to-end timing analysis of the chain. Furthermore, the level of timing information available at various development stages (from modeling of the software architecture to the software implementation) varies a lot, the complete timing information is available only at the implementation stage. This uncertainty and limited timing information can restrict the end-to-end timing analysis of these chains. In this paper, we present methods to compute end-to-end delays based on different levels of system information. The characteristics of different communication semantics are further taken into account, thereby enabling timing analysis throughout the development process of such heterogeneous software systems. The presented methods are evaluated with extensive experiments. As a proof of concept, an industrial case study demonstrates the applicability of the proposed methods following a state-of-the-practice development process.
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| 28. |
- Becker, Matthias, 1986-, et al.
(författare)
-
Extending Automotive Legacy Systems with Existing End-to-End Timing Constraints
- 2018
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Ingår i: 14th International Conference on Information Technology : New Generations ITNG'17. - Cham : Springer International Publishing. - 9783319549774 ; , s. 597-605
-
Konferensbidrag (refereegranskat)abstract
- Developing automotive software is becoming in- creasingly challenging due to continuous increase in its size and complexity. The development challenge is amplified when the industrial requirements dictate extensions to the legacy (previously developed) automotive software while requiring to meet the existing timing requirements. To cope with these challenges, sufficient techniques and tooling to support the modeling and timing analysis of such systems at earlier development phases is needed. Within this context, we focus on the extension of software component chains in the software architectures of automotive legacy systems. Selecting the sampling frequency, i.e. period, for newly added software components is crucial to meet the timing requirements of the chains. The challenges in selecting periods are identified. It is further shown how to automatically assign periods to software components, such that the end-to-end timing requirements are met while the runtime overhead is minimized. An industrial case study is presented that demonstrates the applicability of the proposed solution to industrial problems.
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| 29. |
- Becker, Matthias, et al.
(författare)
-
Investigation on AUTOSAR-Compliant solutions for many-core architectures
- 2015
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Ingår i: Proceedings - 18th Euromicro Conference on Digital System Design, DSD 2015. - 9781467380355 ; , s. 95-103
-
Konferensbidrag (refereegranskat)abstract
- As of today, AUTOSAR is the de facto standard in the automotive industry, providing a common software architecture and development process for automotive applications. While this standard is originally written for singlecore operated Electronic Control Units (ECU), new guidelines and recommendations have been added recently to provide support for multicore architectures. This update came as a response to the steady increase of the number and complexity of the software functions embedded in modern vehicles, which call for the computing power of multicore execution environments. In this paper, we enumerate and analyze the design options and the challenges of porting AUTOSAR-based automotive applications onto multicore platforms. In particular, we investigate those options when considering the emerging many-core architectures that provide a more 'scalable' environment than the traditional multicore systems. Such platforms are suitable to enable massive parallel execution, and their design is more suitable for partitioning and isolating the software components.
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| 30. |
- Becker, Matthias, et al.
(författare)
-
MECHAniSer - A Timing Analysis and Synthesis Tool for Multi-Rate Effect Chains with Job-Level Dependencies
- 2016
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Ingår i: 7th International Workshop on Analysis Tools and Methodologies for Embedded and Real-time Systems WATERS'16.
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Konferensbidrag (refereegranskat)abstract
- Many industrial embedded systems have timing con- straints on the data propagation through a chain of independent tasks. These tasks can execute at different periods which leads to under and oversampling of data. In such situations, understand- ing and validating the temporal correctness of end-to-end delays is not trivial. Many industrial areas further face distributed development where different functionalities are integrated on the same platform after the development process. The large effect of scheduling decisions on the end-to-end delays can lead to expensive redesigns of software parts due to the lack of analysis at early design stages. Job-level dependencies is one solution for this challenge and means of scheduling such systems are available. In this paper we present MECHAniSer, a tool targeting the early analysis of end-to-end delays in multi-rate cause effect chains with specified job-level dependencies. The tool further provides the possibility to synthesize job-level dependencies for a set of cause-effect chains in a way such that all end-to-end requirements are met. The usability and applicability of the tool to industrial problems is demonstrated via a case study.
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