TY - JOUR A1 - Deubzer, Michael A1 - Mottok, Jürgen A1 - Margull, Ulrich A1 - Niemetz, Michael A1 - Wirrer, Gerhard T1 - Efficient Scheduling of Reliable Automotive Multi-core Systems with PD² by Weakening ERfair Task System Requirements JF - Automotive Safety and Security N2 - Partly Proportionate fair (Partly-Pfair) scheduling, which allows task migration at runtime and assigns each task processing time with regard to its weight, makes it possible to build highly efficient embedded multi-core systems. Due to its non-work-conserving behavior, which might leave the CPU idle even when tasks are ready to execute, tasks finish only shortly before their deadlines are reached. Benefits are lower task jitter, but additional workload, e.g. through interrupts, can lead to deadline violations. In this paper we present a work-conserving extension of Partly-Pfair scheduling, called PERfair scheduling and the algorithm P-ERfair-PD2 which applies Pfair modifications used for Partly-Pfair on the concept of ERfairness and PD2 policies. With a simulation based schedulability examination we show for multiple time base (MTB) task sets that P-ERfair- PD2 has the same performance as Partly-Pfair-PD2. Additionally, we show that P-ERfair- PD2 has a much higher robustness against perturbations, and therefore it is well suited for embedded domains, especially for the Automotive domain. Y1 - 2010 UR - https://www.researchgate.net/publication/287883010_Efficient_scheduling_of_reliable_automotive_multi-core_systems_with_pd2_by_weakening_erfair_tasksystem_requirements SP - 53 EP - 67 ER - TY - JOUR A1 - Deubzer, Michael A1 - Schiller, Frank A1 - Mottok, Jürgen A1 - Niemetz, Michael A1 - Margull, Ulrich T1 - Effizientes Multicore-Scheduling in Eingebetteten Systemen – Teil 2: Ein simulationsbasierter Ansatz zum Vergleich von Scheduling-Algorithmen JF - atp - Automatisierungstechnische Praxis N2 - Eingebettete Systeme unterliegen neben den funktionalen Anforderungen besonders nichtfunktionalen Qualitätsanforderungen wie Effizienz, Zuverlässigkeit und Echtzeitfähigkeit. Mit steigendem Bedarf an Rechenkapazität können bisherige Konzepte zur Leistungssteigerung von Singlecore-Systemen jedoch nicht mehr eingesetzt werden - der Umstieg auf Multicore-Systeme wird erforderlich. Im zweiten Teil dieser Arbeit wird ein simulationsbasierter Ansatz zum Vergleich von Multicore-Scheduling-Algorithmen vorgestellt, mit dem Algorithmen für Multicore-Systeme mit voller Migration und dynamischer Task-Priorität untersucht werden. Wir erweitern diesen Ansatz um ein Verfahren zur Untersuchung einer Tasksetmenge mit stochastisch beschriebenen Eigenschaften und vergleichen ihn mit den im Teil 1 beschriebenen Algorithmen BinPacking-EDF und P-ERfair-PD² für eine Gruppe von Automotive Powertrain Systemen. Y1 - 2010 VL - 52 IS - 10 ER - TY - CHAP A1 - Deubzer, Michael A1 - Margull, Ulrich A1 - Mottok, Jürgen A1 - Niemetz, Michael A1 - Wirrer, Gerhard T1 - Partly Proportionate Fair Multiprocessor Scheduling of Heterogeneous Task Systems T2 - 5th Embedded Real Time Software and Systems Conference, May 2010 N2 - Proportionate fair (Pfair) scheduling, which allows task migration at runtime and assigns each task processing time with regard to its weight, is one of the most efficient group of SMP multiprocessor scheduling algorithms known up to now. Drawbacks are tight requirements to the task system, namely the restriction to periodic task systems with synchronized task activation, quantized task execution time, and implicit task deadline. Most likely, a typical embedded real-time system does not fulfill these requirements. In this paper we address violations of these requirements. For heterogeneous task systems, we define the multiple time base (MTB) task system, which is a less pessimistic model than sporadic task systems and is used for automotive systems. We apply the concept of Pfair scheduling to MTB task systems, called partly proportionate fair (Partly-Pfair) scheduling. The restrictions on MTB task systems required for Partly-Pfair ness are weaker than restrictions on periodic task systems required for Pfair ness. In a simulation based study we examined the performance of Partly-Pfair-PD and found it capable to schedule feasible MTB task sets causing a load of up to 100% of the system capacity. Y1 - 2010 ER - TY - CHAP A1 - Deubzer, Michael A1 - Margull, Ulrich A1 - Mottok, Jürgen A1 - Niemetz, Michael A1 - Wirrer, Gerhard T1 - Partitionierungs-Scheduling von Automotive Restricted Tasksystemen auf Multiprozessorplattformen T2 - Proceedings of the 2nd Embedded Software Engineering Congress, 8. bis 10. Dezember 2009, Sindelfingen Y1 - 2009 SP - 536 EP - 542 ER - TY - JOUR A1 - Deubzer, Michael A1 - Schiller, Frank A1 - Mottok, Jürgen A1 - Niemetz, Michael A1 - Margull, Ulrich T1 - Effizientes Multicore-Scheduling in Eingebetteten Systemen – Teil 1: Algorithmen für zuverlässige Echtzeitsysteme JF - atp - Automatisierungstechnische Praxis N2 - Eingebettete Systeme unterliegen neben den funktionalen Anforderungen besonders nicht funktionalen Qualitätsanforderungen wie Effizienz, Zuverlässigkeit und Echtzeitfähigkeit. Mit steigendem Bedarf an Rechenkapazität können bisherige Konzepte zur Leistungssteigerung von Singlecore-Systemen jedoch nicht mehr eingesetzt werden – der Umstieg auf Multicore-Systeme wird erforderlich. Im ersten Teil dieser Arbeit werden eine mögliche Prozessorarchitektur für zukünftige Automotive Multicore-Systeme und die Abstraktion der Software für diese Systeme vorgestellt. Nach einer Klassifkation von Multicore-Scheduling-Algorithmen präsentieren wir exemplarisch einen Algorithmus mit statischer Taskallokation und einen Algorithmus mit dynamischer Taskallokation. Bei beiden Algorithmen handelt es sich um eine Überführung theoretisch behandelter Algorithmen auf Automotive Systeme. Y1 - 2010 UR - https://docplayer.org/4474533-Effizienter-einsatz-von-multicore-systemen.html IS - 9 SP - 60 EP - 67 ER - TY - CHAP A1 - Deubzer, Michael A1 - Hobelsberger, Martin A1 - Mottok, Jürgen A1 - Schiller, Frank A1 - Dumke, Reiner A1 - Siegle, Markus A1 - Margull, Ulrich A1 - Niemetz, Michael A1 - Wirrer, Gerhard T1 - Modeling and Simulation of Embedded Real-Time Multi-Core Systems T2 - Proceedings of the 3rd Embedded Software Engineering Congress, 7. bis 9. Dezember 2010, Sindelfingen KW - Real-Time Systems KW - Multicore KW - Model-Driven Development KW - Architecture Description Language KW - Simulation Y1 - 2010 UR - https://www.unibw.de/technische-informatik/mitarbeiter/professoren/siegle/publikationen/ese2010_muco_modsim.pdf ER - TY - CHAP A1 - Schmidhuber, Stefan A1 - Deubzer, Michael A1 - Mader, Ralph A1 - Niemetz, Michael A1 - Mottok, Jürgen T1 - Towards the Derivation of Guidelines for the Deployment of Real-Time Tasks on a Multicore Processor T2 - 4th International Symposium on Model-Based Safety and Assessment (IMBSA 2014), Munich, Germany, October 27-29, 2014, Proceedings N2 - The deployment of automotive software on a multicore processor includes the task of mapping executables to cores. Given the number of possible solutions, integrators have to solve a complex problem. Considering multiple, often conflicting goals like minimizing task response times and memory consumption, complexity further increased with the advent of multicore processors. We present a model-based approach for deriving design rules supporting integrators with statically mapping tasks to a multicore ECU. First, an evolutionary algorithm is used to sample the design space. For each sample, a model-based analysis is performed, resulting in the required fitness values according to the system metric objectives. Finally, subsets of the sample population are used to derive deployment guidelines by evaluating similarities between highly ranked solutions. This reduces the number of solutions to be considered by the integrators by orders of magnitude. In a case-study, we demonstrate the developed approach on an artificial automotive engine management system. KW - Real-time systems KW - embedded multicore systems KW - runnable partitioning KW - task-to-core mapping KW - software integration KW - design space exploration KW - evolutionary algorithm Y1 - 2014 SN - 978-3-319-12213-7 U6 - https://doi.org/10.1007/978-3-319-12214-4_12 SP - 152 EP - 165 PB - Springer CY - Munich ER -