| 1. |
- Pop, Paul, 1974-, et al.
(författare)
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An Approach to Incremental Design of Distributed Embedded Systems
- 2001
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Ingår i: 38th Design Automation Conference DAC,2001. - Las Vegas, USA : IEEE Computer Society Press. ; , s. 450-455
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Konferensbidrag (refereegranskat)abstract
- In this paper we present an approach to incremental design of distributed embedded systems for hard real-time applications. We start from an already existing system running a set of applications and the design problem is to implement new functionality on this system. Thus, we propose mapping strategies of functionality so that the already running functionality is not disturbed and there is a good chance that, later, new functionality can easily be mapped on the resulted system. The mapping and scheduling for hard real-time embedded systems are considered the context of a realistic communication model. Several experiments demonstrate the efficiency of the approach.
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| 2. |
- Pop, Paul, 1974-, et al.
(författare)
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Minimizing System Modification in an Incremental Design Approach
- 2001
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Ingår i: International Workshop on HardwareSoftware Codesign CODES 2001,2001. - Copenhagen, Denmark : IEEE Computer Society Press. ; , s. 183-
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Konferensbidrag (refereegranskat)abstract
- In this paper we present an approach to mapping and scheduling of distributed embedded systems for hard real-time applications, aiming at minimizing the system modification cost. We consider an incremental design process that starts from an already existing sys-tem running a set of applications. We are interested to implement new functionality so that the already running applications are dis-turbed as little as possible and there is a good chance that, later, new functionality can easily be added to the resulted system. The mapping and scheduling problem are considered in the context of a realistic communication model based on a TDMA protocol.
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| 3. |
- Pop, Paul, et al.
(författare)
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Scheduling and mapping in an incremental design methodology for distributed real-time embedded systems
- 2004
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Ingår i: IEEE Transactions on Very Large Scale Integration (vlsi) Systems. - 1063-8210 .- 1557-9999. ; 12:8, s. 793-811
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Tidskriftsartikel (refereegranskat)abstract
- In this paper, we present an approach to mapping and scheduling of distributed embedded systems for hard real-time applications, aiming at a minimization of the system modification cost. We consider an incremental design process that starts from an already existing system running a set of applications. We are interested in implementing new functionality such that the timing requirements are fulfilled and the following two requirements are also satisfied: 1) the already running applications are disturbed as little as possible and 2) there is a good chance that later, new functionality can easily be added to the resulted system. Thus, we propose a heuristic that finds the set of already running applications which have to be remapped and rescheduled at the same time with mapping and scheduling the new application, such that the disturbance on the running system (expressed as the total cost implied by the modifications) is minimized. Once this set of applications has been determined, we outline a mapping and scheduling algorithm aimed at fulfilling the requirements stated above. The approaches have been evaluated based on extensive experiments using a large number of generated benchmarks as well as a real-life example.
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| 4. |
- Eles, Petru Ion, et al.
(författare)
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Scheduling with bus access optimization for distributed embedded systems
- 2000
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Ingår i: IEEE Transactions on Very Large Scale Integration (vlsi) Systems. - : Institute of Electrical and Electronics Engineers (IEEE). - 1063-8210 .- 1557-9999. ; 8:5, s. 472-491
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Tidskriftsartikel (refereegranskat)abstract
- In this paper, we concentrate on aspects related to the synthesis of distributed embedded systems consisting of programmable processors and application-specific hardware components. The approach is based on an abstract graph representation that captures, at process level, both dataflow and the flow of control. Our goal is to derive a worst case delay by which the system completes execution, such that this delay is as small as possible, to generate a logically and temporally deterministic schedule, and to optimize parameters of the communication protocol such that this delay is guaranteed. We have further investigated the impact of particular communication infrastructures and protocols on the overall performance and, specially, how the requirements of such an infrastructure have to be considered for process and communication scheduling. Not only do particularities of the underlying architecture have to be considered during scheduling but also the parameters of the communication protocol should be adapted to fit the particular embedded application. The optimization algorithm, which implies both process scheduling and optimization of the parameters related to the communication protocol, generates an efficient bus access scheme as well as the schedule tables for activation of processes and communications.
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| 5. |
- Pop, Paul, 1974-
(författare)
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Analysis and Synthesis of Communication-Intensive Heterogeneous Real-Time Systems
- 2003
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Doktorsavhandling (övrigt vetenskapligt/konstnärligt)abstract
- Embedded computer systemsare now everywhere: from alarm clocks to PDAs, from mobile phones to cars, almost all the devices we use are controlled by embedded computer systems. An important class of embedded computer systems is that of real-time systems, which have to fulfill strict timing requirements. As real-time systems become more complex, they are often implemented using distributed heterogeneous architectures. The main objective of the thesis is to develop analysis and synthesis methods for communication-intensive heterogeneous hard real-time systems. The systems are heterogeneous not only in terms of platforms and communication protocols, but also in terms of scheduling policies. Regarding this last aspect, in this thesis we consider time-driven systems, event-driven systems, and a combination of both, called multi-cluster systems. The analysis takes into account the heterogeneous interconnected nature of the architecture, and is based on an application model that captures both the dataflow and the flow of control. The proposed synthesis techniques derive optimized implementations of the system that fulfill the design constraints. An important part of the system implementation is the synthesis of the communication infrastructure, which has a significant impact on the overall system performance and cost. To reduce the time-to-market of products, the design of real-time systems seldom starts from scratch. Typically, designers start from an already existing system, running certain applications, and the design problem is to implement new functionality on top of this system. Hence, in addition to the analysis and synthesis methods proposed, we have also considered mapping and scheduling within such an incremental design process. The analysis and synthesis techniques proposed have been thoroughly evaluated using a solid experimental platform. Besides the evaluations, performed using a large number of generated example applications, we have also validated our approaches using a realistic case study consisting of a vehicle cruise controller.
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| 6. |
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| 7. |
- Pop, Paul, 1974-, et al.
(författare)
-
Analysis and Synthesis of Distributed Real-Time Embedded Systems
- 2004
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Bok (övrigt vetenskapligt/konstnärligt)abstract
- Embedded computer systems are now everywhere: from alarm clocks to PDAs, from mobile phones to cars, almost all the devices we use are controlled by embedded computers. An important class of embedded computer systems is that of hard real-time systems, which have to fulfill strict timing requirements. As real-time systems become more complex, they are often implemented using distributed heterogeneous architectures. Analysis and Synthesis of Distributed Real-Time Embedded Systems addresses the design of real-time applications implemented using distributed heterogeneous architectures. The systems are heterogeneous not only in terms of hardware components, but also in terms of communication protocols and scheduling policies. Regarding this last aspect, time-driven and event-driven systems, as well as a combination of the two, are considered. Such systems are used in many application areas like automotive electronics, real-time multimedia, avionics, medical equipment, and factory systems. The proposed analysis and synthesis techniques derive optimized implementations that fulfill the imposed design constraints. An important part of the implementation processis the synthesis of the communication infrastructure, which has a significant impact on the overall system performance and cost. Analysis and Synthesis of Distributed Real-Time Embedded Systems considers the mapping and scheduling tasks within an incremental design process. To reduce the time-to-market of products, the design of real-time systems seldom starts from scratch. Typically, designers start from an already existing system, running certain applications, and the design problem is to implement new functionality on top of this system. Supporting such an incremental design process provides a high degree of flexibility, and can result in important reductions of design costs. Analysis and Synthesis of Distributed Real-Time Embedded Systems will be of interest to advanced undergraduates, graduate students, researchers and designers involved in the field of embedded systems.
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| 8. |
- Pop, Paul, 1974-, et al.
(författare)
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Design Optimization of Multi-Cluster Embedded Systems for Real-Time Applications
- 2004
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Ingår i: Design, Automation and Test in Europe DATE 2004,2004. - Paris, France : IEEE Computer Society Press. - 0769520855 ; , s. 1028-
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Konferensbidrag (refereegranskat)abstract
- We present an approach to design optimization of multi-cluster embedded systems consisting of time-triggered and event-triggered clusters, interconnected via gateways. In this paper, we address design problems which are characteristic to multi-clusters: partitioning of the system functionality into time-triggered and event-triggered domains, process mapping, and the optimization of parameters corresponding to the communication protocol. We present several heuristics for solving these problems. Our heuristics are able to find schedulable implementations under limited resources, achieving an efficient utilization of the system. The developed algorithms are evaluated using extensive experiments and a real-life example.
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| 9. |
- Pop, Paul, 1974-, et al.
(författare)
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Flexibility Driven Scheduling and Mapping for Distributed Real-Time Systems
- 2002
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Ingår i: 8th International Conference on Real-Time Computing Systems and Applications RTCSA 2002,2002. ; , s. 337-346
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Konferensbidrag (refereegranskat)abstract
- In this paper we present an approach to mapping and scheduling of distributed hard real-time systems, aiming at improving the flexibility of the design process. We consider an incremental design process that starts from an already existing system running a set of applications, with preemptive priority based scheduling at the process level, and time triggered static scheduling at the communication level. We are interested to implement new functionality so that the already running applications are disturbed as little as possible and there is a good chance that, later, new functionality can easily be added to the resulted system. The mapping and scheduling problems are considered in the context of a realistic communication model based on a TDMA protocol. Extensive experiments as well as a real life example demonstrate the relevance of this problem and the efficiency of our solutions.
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| 10. |
- Pop, Paul, 1974-, et al.
(författare)
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Performance Estimation for Embedded Systems with Data and Control Dependencies
- 2000
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Ingår i: 8th International Workshop on HardwareSoftware Codesign CODES 2000,2000. - San Diego, USA : IEEE Computer Society Press. - 1581132689 ; , s. 62-66
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Konferensbidrag (refereegranskat)abstract
- In this paper we present an approach to performance estimation for hard real-time systems. We consider architectures consisting of multiple processors. The scheduling policy is based on a preemptive strategy with static priorities. Our model of the system captures both data and control dependencies, and the analysis is able to reduce the pessimism of the estimation by using the knowledge about these dependencies. Extensive experiments as well as a real life example demonstrate the efficiency of our approach.
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| 11. |
- Pop, Paul, 1974-, et al.
(författare)
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Schedulability Analysis and Optimization for the Synthesis of Multi-Cluster Distributed Embedded Systems
- 2003
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Ingår i: IEE journal on computers and digital techniques / Institution of electrical engineers. - Munich, Germany : IEEE Computer Society Press. - 0140-1335. ; 150:5, s. 303-312, s. 184-
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Tidskriftsartikel (refereegranskat)abstract
- We present an approach to schedulability analysis for the synthesis of multicluster distributed embedded systems consisting of time-triggered and event-triggered clusters, interconnected via gateways. We have also proposed a buffer size and worst-case queuing delay analysis for the gateways, responsible for routing inter-cluster traffic. Optimization heuristics for the priority assignment and synthesis of bus access parameters aimed at producing a schedulable system with minimal buffer needs have been proposed. Extensive experiments and a real-life example show the efficiency of our approaches.
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| 12. |
- Pop, Paul, 1974-, et al.
(författare)
-
Schedulability Analysis for Systems with Data and Control Dependencies
- 2000
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Ingår i: 12th Euromicro Conference on Real-Time Systems,2000. - Stockholm, Sweden : IEEE Computer Society Press. - 0769507344 ; , s. 201-208
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Konferensbidrag (refereegranskat)abstract
- In this paper we present an approach to schedulability analysis for hard real-time systems with control and data dependencies. We consider distributed architectures consisting of multiple programmable processors, and the scheduling policy is based on a static priority preemptive strategy. Our model of the system captures both data and control dependencies, and the schedulability approach is able to reduce the pessimism of the analysis by using the knowledge about control and data dependencies. Extensive experiments as well as a real life example demonstrate the efficiency of our approach.
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| 13. |
- Pop, Paul, 1974-, et al.
(författare)
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Schedulability-Driven Communication Synthesis for Time-Triggered Embedded Systems
- 2004
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Ingår i: Real-time systems. - 0922-6443 .- 1573-1383. ; 26:3, s. 297-325
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Tidskriftsartikel (refereegranskat)abstract
- We present an approach to static priority preemptive process scheduling for the synthesis of hard real-time distributed embedded systems where communication plays an important role. The communication model is based on a time-triggered protocol. We have developed an analysis for the communication delays with four different message scheduling policies over a time-triggered communication channel. Optimization strategies for the synthesis of communication are developed, and the four approaches to message scheduling are compared using extensive experiments.
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| 14. |
- Pop, Paul, 1974-, et al.
(författare)
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Schedulability-Driven Frame Packing for Multi-Cluster Distributed Embedded Systems
- 2003
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Ingår i: LCTES '03 Proceedings of the 2003 ACM SIGPLAN conference on Language, compiler, and tool for embedded systems. - New York, NY, United States : Association for Computing Machinery (ACM). - 1581136471 ; , s. 113-122
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Konferensbidrag (övrigt vetenskapligt/konstnärligt)abstract
- We present an approach to frame packing for multi-cluster distributed embedded systems consisting of time-triggered and event-triggered clusters, interconnected via gateways. In our approach, the application messages are packed into frames such that the application is schedulable. Thus, we have also proposed a schedulability analysis for applications consisting of mixed event-triggered and time-triggered processes and messages, and a worst case queuing delay analysis for the gateways, responsible for routing inter-cluster traffic. Optimization heuristics for frame packing aiming at producing a schedulable system have been proposed. Extensive experiments and a real-life example show the efficiency of our frame-packing approach.
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| 15. |
- Pop, Paul, 1974-, et al.
(författare)
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Schedulability-Driven Partitioning and Mapping for Multi-Cluster Real-Time Systems
- 2004
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Ingår i: 16th Euromicro Conference on Real-Time Systems,2004. - Catania, Sicily : IEEE Computer Society Press. - 0769521762 ; , s. 91-
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Konferensbidrag (refereegranskat)abstract
- We present an approach to partitioning and mapping for multi-cluster embedded systems consisting of time-triggered and event-triggered clusters, interconnected via gateways. We have proposed a schedulability analysis for such systems, including a worst-case queuing delay analysis for the gateways, responsible for routing inter-cluster traffic. Based on this analysis, we address design problems which are characteristic to multi-clusters: partitioning of the system functionality into time-triggered and event-triggered domains, and process mapping. We present a branch and bound algorithm for solving these problems. Our heuristic is able to find schedulable implementations under limited resources, achieving an efficient utilization of the system. The developed algorithms are evaluated using extensive experiments and a real-life example.
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| 16. |
- Pop, Paul, 1974-
(författare)
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Scheduling and Communication Synthesis for Distributed Real-Time Systems
- 2000
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Licentiatavhandling (övrigt vetenskapligt/konstnärligt)abstract
- Embedded systems are now omnipresent: from cellular phones to pagers, from microwave ovens to PDAs, almost all the devices we use are controlled by embedded systems. Many embedded systems have to fulfill strict requirements in terms of performance and cost efficiency. Emerging designs are usually based on heterogeneous architectures that integrate multiple programmable processors and dedicated hardware components. New tools which extend design automation to system level have to support the integrated design of both the hardware and software components of such systems. This thesis concentrates on aspects of scheduling and communication for embedded real-time systems. Special emphasis has been placed on the impact of the communication infrastructure and protocol on the overall system performance. The scheduling and communication strategies proposed are based on an abstract graph representation which captures, at process level, both the dataflow and the flow of control. We have considered non-preemptive static cyclic scheduling and preemptive scheduling with static priorities for the scheduling of processes, while the communications are statically scheduled according to the time triggered protocol. We have developed static cyclic scheduling algorithms for time-driven systems with control and data dependencies. We show that by considering aspects of the communication protocol, significant improvements can be gained in the schedule quality. In the context of event-driven systems we have proposed a less pessimistic schedulability analysis that is able to handle both control and data dependencies. Moreover, we have provided a schedulability analysis for the time-triggered protocol, and we have proposed several optimization strategies for the synthesis of communication protocol parameters. Extensive experiments as well as real-life examples demonstrate the efficiency of our approaches.
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| 17. |
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