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Moghaddami Khalilzad, NimaORCID iD iconorcid.org/0000-0003-2670-3022
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Publications (10 of 29) Show all publications
Ashjaei, M., Khalilzad, N., Mubeen, S., Behnam, M., Sander, I., Almeida, L. & Nolte, T. (2017). Designing End-to-end Resource Reservations in Predictable Distributed Embedded Systems. Real-time systems, 53(6), 916-956
Open this publication in new window or tab >>Designing End-to-end Resource Reservations in Predictable Distributed Embedded Systems
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2017 (English)In: Real-time systems, ISSN 0922-6443, E-ISSN 1573-1383, Vol. 53, no 6, p. 916-956Article in journal (Refereed) Published
Abstract [en]

Contemporary distributed embedded systems in many domains have become highly complex due to ever-increasing demand on advanced computer controlled functionality. The resource reservation techniques can be effective in lowering the software complexity, ensuring predictability and allowing flexibility during the development and execution of these systems. This paper proposes a novel end-to-end resource reservation model for distributed embedded systems. In order to support the development of predictable systems using the proposed model, the paper provides a method to design resource reservations and an end-to-end timing analysis. The reservation design can be subjected to different optimization criteria with respect to runtime footprint, overhead or performance. The paper also presents and evaluates a case study to show the usability of the proposed model, reservation design method and end-to-end timing analysis. 

National Category
Computer Systems
Identifiers
urn:nbn:se:mdh:diva-35506 (URN)10.1007/s11241-017-9283-6 (DOI)000412536700004 ()2-s2.0-85020515685 (Scopus ID)
Projects
PRESS - Predictable Embedded Software SystemsFuture factories in the CloudPreView: Developing Predictable Vehicle Software on Multi-core
Available from: 2017-05-31 Created: 2017-05-31 Last updated: 2018-07-25Bibliographically approved
Afshar, S., Khalilzad, N., Behnam, M., Bril, R. J. & Nolte, T. (2016). Intra-component Resource Sharing on a Virtual Multiprocessor Platform. In: ACM SIGBED Review: Special Issue on 8th International Workshop on Compositional Theory and Technology for Real-Time Embedded Systems. Paper presented at 8th International Workshop on Compositional Theory and Technology for Real-Time Embedded Systems CRTS'15, 01 Dec 2015, San Antonio, United States (pp. 31-32).
Open this publication in new window or tab >>Intra-component Resource Sharing on a Virtual Multiprocessor Platform
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2016 (English)In: ACM SIGBED Review: Special Issue on 8th International Workshop on Compositional Theory and Technology for Real-Time Embedded Systems, 2016, p. 31-32Conference paper, Published paper (Refereed)
Abstract [en]

Component-based software development facilitates the development process of large and complex software systems. By the advent of multiprocessors, the independently developed components can be integrated on a multi-core platform to achieve an efficient use of system hardware and a decrease in system power consumption and costs. In this paper, we consider a virtual multiprocessor platform where each component can be dynamically allocated to any set of processors of the platform with a maximum concurrency level. Global-EDF is used for intra-component scheduling. The existing analysis for such systems have assumed that tasks are independent. In this paper, we enable intra-component resource sharing for this platform. We investigate using a spin-based resource sharing protocol with the accompanying analysis that extends the existing analysis for independent tasks. We briefly illustrate and evaluate our initial results with an example.

National Category
Computer Systems
Identifiers
urn:nbn:se:mdh:diva-32777 (URN)10.1145/2983185.2983190 (DOI)
External cooperation:
Conference
8th International Workshop on Compositional Theory and Technology for Real-Time Embedded Systems CRTS'15, 01 Dec 2015, San Antonio, United States
Projects
PRESS - Predictable Embedded Software Systems
Available from: 2016-09-01 Created: 2016-08-24 Last updated: 2016-09-01Bibliographically approved
Moghaddami Khalilzad, N., Ashjaei, S. M., Mubeen, S., Behnam, M. & Sander, I. (2016). Towards Designing Efficient End-to-end Resource Reservations for Distributed Embedded Systems. In: Forum on specification & Design Languages FDL'16: . Paper presented at Forum on specification & Design Languages FDL'16, 14 Sep 2016, Bremen, Germany. Bremen, Germany
Open this publication in new window or tab >>Towards Designing Efficient End-to-end Resource Reservations for Distributed Embedded Systems
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2016 (English)In: Forum on specification & Design Languages FDL'16, Bremen, Germany, 2016Conference paper, Published paper (Refereed)
Place, publisher, year, edition, pages
Bremen, Germany: , 2016
National Category
Computer Systems
Identifiers
urn:nbn:se:mdh:diva-36991 (URN)
Conference
Forum on specification & Design Languages FDL'16, 14 Sep 2016, Bremen, Germany
Projects
PRESS - Predictable Embedded Software SystemsDPAC - Dependable Platforms for Autonomous systems and Control
Available from: 2017-11-27 Created: 2017-11-27 Last updated: 2017-11-27Bibliographically approved
Khalilzad, N., Kong, F., Liu, X., Behnam, M. & Nolte, T. (2015). A Feedback Scheduling Framework for Component-Based Soft Real-Time Systems. In: 21th IEEE Real-Time and Embedded Technology and Applications Symposium RTAS'15: . Paper presented at 21th IEEE Real-Time and Embedded Technology and Applications Symposium RTAS'15, 13-16 Apr 2015, Seattle, United States (pp. 182-193).
Open this publication in new window or tab >>A Feedback Scheduling Framework for Component-Based Soft Real-Time Systems
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2015 (English)In: 21th IEEE Real-Time and Embedded Technology and Applications Symposium RTAS'15, 2015, p. 182-193Conference paper, Published paper (Refereed)
Abstract [en]

Component-based software systems with real-time requirements are often scheduled using processor reservation techniques. Such techniques have mainly evolved around hard real-time systems in which worst-case resource demands are considered for the reservations. In soft real-time systems, reserv- ing the processors based on the worst-case demands results in unnecessary over-allocations. In this paper, targeting soft real-time systems running on multiprocessor platforms, we focus on components for which processor demand varies during run-time. We propose a feedback scheduling frameworkwhere processor reservations are used for scheduling components. The reservation bandwidths as well as the reservation periods are adapted using MIMO LQR controllers. We provide an allocation mechanism for distributing components over processors. The proposed framework is implemented in the TrueTime simulation tool for system identification. We use a case study to investigate the performance of our framework in the simulation tool. Finally, the framework is implemented in the Linux kernel for practical evaluations. The evaluation results suggest that the framework can efficiently adapt the reservation parameters during run-time by imposing negligible overhead.

National Category
Computer and Information Sciences
Identifiers
urn:nbn:se:mdh:diva-28130 (URN)10.1109/RTAS.2015.7108441 (DOI)000380616700016 ()2-s2.0-84944682349 (Scopus ID)978-1-4799-8603-3 (ISBN)
External cooperation:
Conference
21th IEEE Real-Time and Embedded Technology and Applications Symposium RTAS'15, 13-16 Apr 2015, Seattle, United States
Projects
ARROWS - Design Techniques for Adaptive Embedded Systems
Available from: 2015-06-11 Created: 2015-06-08 Last updated: 2018-01-11Bibliographically approved
Khalilzad, N. (2015). Adaptive and Flexible Scheduling Frameworks for Component-Based Real-Time Systems. (Doctoral dissertation). Västerås: Mälardalen University
Open this publication in new window or tab >>Adaptive and Flexible Scheduling Frameworks for Component-Based Real-Time Systems
2015 (English)Doctoral thesis, comprehensive summary (Other academic)
Abstract [en]

Modern computer systems are often designed to play a multipurpose role. Therefore, they are capable of running a number of software components (software programs) simultaneously in parallel. These software components should share the system resources (e.g. processor and network) such that all of them run and finish their computations as expected. On the other hand, a number of software components have timing requirements meaning that they should not only access the resources, but this access should also be in a timely manner. Thus, there is a need to timely share the resources among different software components. The time-sharing is often realized by reserving a time-portion of resources for each component. Such a reservation should be adequate and resource-efficient. It should be sufficient to preserve the timing properties of the components. Also, the reservations should be resource-efficient to reduce the components' footprint on the resources which in turn allows integration of more software components on a given hardware resource. In this thesis, we mainly focus on the resource-efficiency of the reservations. We consider two cases. (I) Components which can tolerate occasional timing violations (soft real-time components): in this case we adjust the reservations during run-time to match the reservation sizes based on the instantaneous requirements of the components. (II) Components which cannot tolerate any timing violations (hard real-time components): in this case we use flexible approaches which allow us to improve the resource-efficiency at the design time.

Abstract [sv]

Moderna datasystem är ofta utformade för att spela en mångsidig roll. De är därför kapabla till att köra flera mjukvarukomponenter (programvaror) samtidigt. Dessa mjukvarukomponenter delar systemresurser (t.ex. processorn och nätverket) under körning. Målet med mjukvarukomponentens körning är att avsluta sina beräkningar som förväntat. Vissa mjukvarukomponenter har även tidskrav vilket innebär att de inte bara kräver tillgång till systemresurser för att köra sina beräkningar, utan de har även krav på när denna tillgång sker för att mjukvarukomponenterna ska för rätt funktion kunna garantera att beräkningar utförs i rätt tid. Således finns det ett behov av att snabbt dela resurser mellan olika mjukvarukomponenter. Den tids-delning realiseras ofta genom att reservera en tidslucka för komponenten då denna är tänkt att och får använda resursen. Reservationen måste vara tillräcklig för att mjukvarukomponenten ska kunna köra som förväntat. Reservationen måste även tilldelas resurseffektivt dvs resurstid får inte slösas bort i onödan. Genom en resurseffektiv reservation av resurserminskar komponentens fotavtryck på resursen som i sin tur möjliggör integration av flera programvarukomponenter på samma resurs. Denna avhandling fokuserar främst på resurseffektivitet i samband med reservationerna. Två fall behandlas. (I) Komponenter som tål att missa vissa enstaka tidskrav (så kallade mjuka realtidskomponenter): i det här fallet anpassas reservationerna under körning enligt komponenternas ständigt föränderliga önskemål på reservationsstorlek. (II) Komponenter som inte kan hantera att tidskrav överträds (så kallade hårda realtidskomponenter): i det här fallet används flexibla strategier som möjliggör  förbättrad resurseffektiviteten redan vid design av systemet.

Place, publisher, year, edition, pages
Västerås: Mälardalen University, 2015
Series
Mälardalen University Press Dissertations, ISSN 1651-4238 ; 191
National Category
Computer Engineering
Identifiers
urn:nbn:se:mdh:diva-29110 (URN)978-91-7485-235-6 (ISBN)
Public defence
2015-11-05, Lambda, Mälardalens högskola, Västerås, 13:15 (English)
Opponent
Supervisors
Available from: 2015-09-24 Created: 2015-09-23 Last updated: 2018-01-11Bibliographically approved
Khalilzad, N., Ashjaei, M., Almeida, L., Behnam, M. & Nolte, T. (2015). Adaptive Multi-Resource End-to-End Reservations for Component-Based Distributed Real-Time Systems. In: ESTIMedia 2015 - 13th IEEE Symposium on Embedded Systems for Real-Time Multimedia: . Paper presented at IEEE Symposium on Embedded Systems for Real-Time Multimedia. October 8-9, 2015. Amsterdam, The Netherlands. (pp. Article number 7351772).
Open this publication in new window or tab >>Adaptive Multi-Resource End-to-End Reservations for Component-Based Distributed Real-Time Systems
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2015 (English)In: ESTIMedia 2015 - 13th IEEE Symposium on Embedded Systems for Real-Time Multimedia, 2015, p. Article number 7351772-Conference paper, Published paper (Refereed)
Abstract [en]

Complexity in the real-time embedded softwaredomain has been growing rapidly. The component-based softwaredevelopment approach facilitates the development process of suchsoftware systems by dividing a complex system into a numberof simpler components. Resource reservation techniques havebeen widely used for providing resources to real-time softwarecomponents. In this paper we target real-time components operatingon a distributed resource infrastructure. Furthermore,we target a class of software components which demonstratedynamic resource consumption behavior. A prime example ofsuch components is a multimedia software component. In thepaper, we present a framework supporting multi-resource endto-end resource reservations. We reserve resource bandwidths onboth processor resources as well as on the network resources. Theproposed framework utilizes a Multiple Input Multiple Output(MIMO) controller which adjusts the sizes of reservations trackingthe dynamic resource demands of the software components. Finally, we present a case study using a multimedia component todemonstrate the performance and efficiency of our framework.

National Category
Computer Engineering
Identifiers
urn:nbn:se:mdh:diva-29106 (URN)10.1109/ESTIMedia.2015.7351772 (DOI)000377587200013 ()2-s2.0-84962285268 (Scopus ID)978-146738164-2 (ISBN)
Conference
IEEE Symposium on Embedded Systems for Real-Time Multimedia. October 8-9, 2015. Amsterdam, The Netherlands.
Available from: 2015-09-23 Created: 2015-09-23 Last updated: 2018-01-11Bibliographically approved
Khalilzad, N., Behnam, M. & Nolte, T. (2015). An Adaptive Scheduling Framework for Component-Based Real-Time Systems.
Open this publication in new window or tab >>An Adaptive Scheduling Framework for Component-Based Real-Time Systems
2015 (English)Report (Other academic)
National Category
Computer Engineering
Identifiers
urn:nbn:se:mdh:diva-29109 (URN)
Available from: 2015-09-23 Created: 2015-09-23 Last updated: 2018-01-11Bibliographically approved
Becker, M., Khalilzad, N., Bril, R. J. & Nolte, T. (2015). Extended support for limited preemption fixed priority scheduling for OSEK/AUTOSAR-compliant operating systems. In: 2015 10th IEEE International Symposium on Industrial Embedded Systems, SIES 2015 - Proceedings: . Paper presented at 10th IEEE International Symposium on Industrial Embedded Systems, SIES 2015; Siegen; Germany; 8 June 2015 through 10 June 2015 (pp. 207-217).
Open this publication in new window or tab >>Extended support for limited preemption fixed priority scheduling for OSEK/AUTOSAR-compliant operating systems
2015 (English)In: 2015 10th IEEE International Symposium on Industrial Embedded Systems, SIES 2015 - Proceedings, 2015, p. 207-217Conference paper, Published paper (Refereed)
Abstract [en]

Fixed Priority Scheduling (FPS) is the de facto standard in industry and it is the scheduling algorithm used in OSEK/AUTOSAR. Applications in such systems are compositions of so called runnables, the functional entities of the system. Runnables are mapped to operating system tasks during system synthesis. In order to improve system performance it is proposed to execute runnables non-preemptively while varying the tasks threshold between runnables. This allows simpler resource access, can reduce the stack usage of the system, and improve the schedulability of the task sets. FPDS , as a special case of fixed-priority scheduling with deferred preemptions, executes subjobs non-preemptively and preemption points have preemption thresholds, providing exactly the proposed behavior. However OSEK/AUTOSAR-conform systems cannot execute such schedules. In this paper we present an approach allowing the execution of FPDS schedules. In our approach we exploit pseudo resources in order to implement FPDS . It is further shown that our optimal algorithm produces a minimum number of resource accesses. In addition, a simulation based evaluation is presented in which the number of resource accesses as well as the number of required pseudo-resources by the proposed algorithms are investigated. Finally, we report the overhead of resource access primitives using our measurements performed on an AUTOSARcompliant operating system.

Keywords
Limited Preemptive Fixed Priority Scheduling AUTOSAROSEKPseudo Resources
National Category
Computer and Information Sciences
Identifiers
urn:nbn:se:mdh:diva-28151 (URN)10.1109/SIES.2015.7185062 (DOI)000380569800028 ()2-s2.0-84959459867 (Scopus ID)9781467377119 (ISBN)
External cooperation:
Conference
10th IEEE International Symposium on Industrial Embedded Systems, SIES 2015; Siegen; Germany; 8 June 2015 through 10 June 2015
Projects
START - Stochastic Real-Time Analysis of Embedded Software SystemsARROWS - Design Techniques for Adaptive Embedded Systems
Available from: 2015-06-12 Created: 2015-06-08 Last updated: 2018-01-11Bibliographically approved
Khalilzad, N., Behnam, M. & Nolte, T. (2015). On Component-Based Software Development for Multiprocessor Real-Time Systems. In: Proceedings - IEEE 21st International Conference on Embedded and Real-Time Computing Systems and Applications, RTCSA 2015: . Paper presented at 21st IEEE International Conference on Embedded and Real-Time Computing Systems and Applications. August 19-21, 2015. Hong Kong, China. (pp. 132-140).
Open this publication in new window or tab >>On Component-Based Software Development for Multiprocessor Real-Time Systems
2015 (English)In: Proceedings - IEEE 21st International Conference on Embedded and Real-Time Computing Systems and Applications, RTCSA 2015, 2015, p. 132-140Conference paper, Published paper (Refereed)
Abstract [en]

Component-based software development providesa modular approach to develop complex software systems. In the context of real-time systems, it is desirable to abstract the timing properties of software components using an interface foreach component. The timing properties of the whole system, composed of multiple components, is studied using the component interfaces. In this paper we focus on periodic interface models. In the case of components developed for single processor platforms, for examining the system schedulability, the interfaces can be regarded as periodic tasks. Thus, making it possible to use the conventional schedulability analyses for the system level schedulability test. In the case of components developed formultiprocessors, since interfaces may have utilization larger than 100 % of a single processor, it is not possible to directly use the component interfaces for the system schedulability test. There-fore, the interfaces have to be decomposed before performing thesystem level schedulability test. In this paper, we target the special case of partitioned EDF for scheduling the components integrated on a multiprocessor. Therefore, the system level schedulability test is equivalent to finding a feasible allocation of component interfaces on the multiprocessor. We propose two algorithms for allocating the multiprocessor periodic interfaces. In addition, we propose anorthogonal approach for developing component-based real-timesystems on multiprocessors in which components with utilizationmore than 100 % of a single processor are divided into smaller subcomponents before abstracting their interfaces. We show, through extensive evaluations, that our alternative approach significantly reduces the interface overhead.

National Category
Computer Engineering Computer Engineering
Identifiers
urn:nbn:se:mdh:diva-29108 (URN)10.1109/RTCSA.2015.27 (DOI)000378419800014 ()2-s2.0-84962803719 (Scopus ID)9781467378550 (ISBN)
Conference
21st IEEE International Conference on Embedded and Real-Time Computing Systems and Applications. August 19-21, 2015. Hong Kong, China.
Available from: 2015-09-23 Created: 2015-09-23 Last updated: 2018-01-11Bibliographically approved
Afshar, S., Moghaddami Khalilzad, N., Nemati, F. & Nolte, T. (2015). Resource Sharing among Prioritized Real-Time Applications on Multiprocessors. In: ACM SIGBED Review - Special Issue on the 6th International Workshop on Compositional Theory and Technology for Real-Time Embedded Systems Homepage archiveVolume 12 Issue 1: . Paper presented at 6th Workshop on Compositional Theory and Technology for Real-Time Embedded Systems, Vancouver, Canada, 2013 (pp. 46-55).
Open this publication in new window or tab >>Resource Sharing among Prioritized Real-Time Applications on Multiprocessors
2015 (English)In: ACM SIGBED Review - Special Issue on the 6th International Workshop on Compositional Theory and Technology for Real-Time Embedded Systems Homepage archiveVolume 12 Issue 1, 2015, p. 46-55Conference paper, Published paper (Refereed)
Abstract [en]

In this paper, we propose a new protocol for handling resource sharing among prioritized real-time applications composed on a multiprocessor platform. We propose an optimal priority assignment algorithm which assigns unique priorities to the applications based on information in their interfaces. We have performed experimental evaluations to compare the proposed protocol (called MSOS-Priority) to the current state of the art locking protocols under multiprocessor partitioned scheduling, i.e., MPCP, MSRP, FMLP, MSOS, and OMLP. The valuations show that MSOS-Priority mostly performs significantly better than alternative approaches.

National Category
Computer Systems
Identifiers
urn:nbn:se:mdh:diva-23320 (URN)10.1145/2752801.2752807 (DOI)
Conference
6th Workshop on Compositional Theory and Technology for Real-Time Embedded Systems, Vancouver, Canada, 2013
Projects
PRESS - Predictable Embedded Software Systems
Available from: 2013-12-12 Created: 2013-12-10 Last updated: 2019-07-18Bibliographically approved
Organisations
Identifiers
ORCID iD: ORCID iD iconorcid.org/0000-0003-2670-3022

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