Szenarien in vernetzten Multicore-Systemen - Analyse und Optimierung.
Zusammenfassung der Projektergebnisse
Providing timing guarantees is one of the key aspects of system architecture design and has been recognized as a major challenge when designing timing-critical systems. Many realtime embedded systems, e.g. from the automotive and avionic domain, execute multi-mode applications, i.e. applications that can change their functionality over time. As multi-core architectures emerge as the prevalent platform for embedded real-time applications the design process of embedded real-time systems faces new challenges generated by the need to accommodate multi-mode applications on multi-core systems. Appropriate mechanisms that jointly handle the mode management, multi-core scheduling and shared resource arbitration are required in order to ensure correct system functionality. Consequently, proper timing analysis methods for the prediction of timing behavior of multi-mode applications on multi-core systems are needed and their development was the main goal of this project. The starting point of the project was the modular scalable performance analysis methodology and the corresponding tool SymTA/S, which are very appropriate for the analysis of complex real-time systems. This framework has been extended in this project for the analysis of distributed multi-mode applications which share common resources on multi-core systems. First, we developed new approaches for the analysis of worst-case blocking- and responsetimes for tasks that share resources in multi-core systems. The analysis approaches cover realistic system configurations with tasks that exhibit arbitrary activations and deadlines and rely on a sophisticated model to capture the load imposed on the shared resources. Furthermore, the proposed approaches suit the upcoming automotive multi-core processors using the AUTOSAR standard where preemptive and non-preemptive scheduling will coexists and where accesses to shared hardware and logical resources (e.g. coprocessors, I/O ports, semaphores) will be arbitrated according to a spin-based locking protocol. The extended analysis framework was also applied to investigate the impact of different design decisions regarding task scheduling (e.g. preemptive vs. non-preemptive) and shared resource arbitration on the application timing. Furthermore, we worked on the timing analysis of distributed multi-mode systems. Preliminary own work identified that changing modes in distributed systems might induce transient overload situations and thus challenge the real-time system behavior. In this project we developed an analysis algorithm which determines a maximum bound on the settling time of a mode change (called mode change transition latency) of multi-mode distributed applications. In the last phase of the project the multi-core and multi-mode related analysis methods were combined in order to address the complex problem of designing and analyzing setups consisting of multi-mode applications mapped on multi-core systems with shared resources. The analysis methods and a corresponding test-case generator were implemented as plugins for the academic version of the tool SymTA/S and can be used for automatic schedulability analysis and to guide the designers’ decisions regarding the implementation and the mapping of multi-mode real-time applications on multi-core systems. The extended SymTA/S analysis framework suits the next generation of automotive multi-core processors using the AUTOSAR standard where applications will be scheduled using a partitioned fixedpriority scheduling, will share resources according to a spinlock-based mechanism and will be subject to mode management. The coupling of the analysis plugins with SymTA/S facilitates the evaluation of the research methods by industrial and research partners and actively contributes to increase the popularity of formal methods in the automotive domain. The proposed approaches have been presented at leading conferences and in scientific journals and demonstrated at university booths. The SymTA/S tool was used for the experimental evaluations which we performed for several publications. It also served as demonstrator in the context of different national and international project meetings and conferences.
Projektbezogene Publikationen (Auswahl)
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"Bounding the Shared Resource Load for the Performance Analysis of Multiprocessor Systems" in Proc. of Design, Automation, and Test in Europe (DATE), (Dresden, Germany), March 2010
Simon Schliecker, Mircea Negrean and Rolf Ernst
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"Timing Implications of Sharing Resources in Multicore Real-Time Automotive Systems", SAE International Journal of Passenger Cars - Electronic and Electrical Systems, vol. 3, No. 1, pp. 27-40, August 2010
Mircea Negrean, Simon Schliecker and Rolf Ernst
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"Bounding Mode Change Transition Latencies for Multi-Mode Real-Time Distributed Applications" in 16th IEEE International Conference on Emerging Technologies and Factory Automation (ETFA'11), (Toulouse, France), September 2011
Mircea Negrean, Moritz Neukirchner, Steffen Stein, Simon Schliecker and Rolf Ernst
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"Mastering MPSoCs for Mixed-Critical Applications", IPSJ Transactions on System LSI Design Methodology, vol. 4, August 2011
Philip Axer, Jonas Diemer, Mircea Negrean, Maurice Sebastian, Simon Schliecker and Rolf Ernst
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"Mastering Timing Challenges for the Design of Multi-Mode Applications on Multi-Core Real-Time Embedded Systems" in 6th International Congress on Embedded Real-Time Software and Systems (ERTS), (Toulouse, France), February 2012
Mircea Negrean, Rolf Ernst and Simon Schliecker
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"Response-Time Analysis for Non-Preemptive Scheduling in Multi-Core Systems with Shared Resources" in Proc. of 7th IEEE International Symposium on Industrial Embedded Systems (SIES), (Karlsruhe, Germany), June 2012
Mircea Negrean and Rolf Ernst
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"System Level Performance Analysis for Real-Time Multi-Core and Network Architectures". In Advances in Real-Time Systems, pp. 171 - 189, Springer. 2012
Jonas Rox, Mircea Negrean, Simon Schliecker and Rolf Ernst
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"Timing Analysis of Multi-Mode Applications on AUTOSAR conform Multi-Core Systems" in Proc. of Design, Automation and Test in Europe (DATE), (Grenoble, France), March 2013
Mircea Negrean, Sebastian Klawitter and Rolf Ernst
