The Experts below are selected from a list of 1806 Experts worldwide ranked by ideXlab platform
C Krakowski - One of the best experts on this subject based on the ideXlab platform.
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Interrupt Service threads a new approach to handle multiple hard real time events on a multithreaded microcontroller
2007Co-Authors: Uwe Brinkschulte, C Krakowski, J Kreuzinger, Th UngererAbstract:We propose a new event handling mechanism based on a multithreaded microcontroller, that allows efficient handling of simultaneous overlapping events with hard realtime requirements. Real-time threads are used as Interrupt Service threads (ISTs) instead of Interrupt Service routines (ISRs). ISTs are executed on a multithreaded microcontroller that supports multiple concurrently executing ISTs. Several thread priority schemes are managed in hardware, in particular, we propose a guaranteed percentage scheme where each real-time thread is assigned a rate of the full processing power. We show an analytical evaluation of the IST technique and the guaranteed percentage scheme using real-time requirements of an autonomous guided vehicle. The evaluations show that the ISR solution with the fixed priority preemptive scheme isn’t able to guarantee the specified deadlines, in contrast to the IST solution, that even offers a spare of 5%. Moreover, in our case guaranteed percentage scheduling offers an advantage over EDF scheduling, if not only deadlines, but also data rates must be met. When calculating the maximum vehicle speed without violating the real-time constraints ISTs dominate ISRs by a speed increase of 28%.
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RTCSA - Real-time scheduling on multithreaded processors
Proceedings Seventh International Conference on Real-Time Computing Systems and Applications, 2000Co-Authors: J Kreuzinger, Uwe Brinkschulte, A. Schulz, M. Pfeffer, T. Ungerer, C KrakowskiAbstract:This paper investigates real-time scheduling algorithms on upcoming multithreaded processors. As evaluation testbed we introduce a multithreaded processor kernel which is specifically designed as core processor of a micro-controller or system-on-a-chip. Handling of external real-time events is performed through multithreading. Real-time threads are used as Interrupt Service threads (ISTs) instead of Interrupt Service routines (ISRs). Our proposed micro-controller supports multiple ISTs with zero-cycle context switching overhead. We investigate the behavior of fixed priority preemptive, earliest deadline first, least laxity first and guaranteed percentage scheduling with respect to multithreaded processors. Our finding is that the strategies GP and LLF result in a good blending of instructions of different threads thus enabling a multithreaded processor to utilize latencies best. Assuming a zero-cycle context switch LLF performs best, however implementation cost context, are prohibitive.
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Real-time scheduling on multithreaded processors
Proceedings Seventh International Conference on Real-Time Computing Systems and Applications, 2000Co-Authors: J Kreuzinger, A. Schulz, M. Pfeffer, T. Ungerer, U. Brinkschulte, C KrakowskiAbstract:This paper investigates real-time scheduling algorithms on upcoming multithreaded processors. As evaluation testbed we introduce a multithreaded processor kernel which is specifically designed as core processor of a micro-controller or system-on-a-chip. Handling of external real-time events is performed through multithreading. Real-time threads are used as Interrupt Service threads (ISTs) instead of Interrupt Service routines (ISRs). Our proposed micro-controller supports multiple ISTs with zero-cycle context switching overhead. We investigate the behavior of fixed priority preemptive, earliest deadline first, least laxity first and guaranteed percentage scheduling with respect to multithreaded processors. Our finding is that the strategies GP and LLF result in a good blending of instructions of different threads thus enabling a multithreaded processor to utilize latencies best. Assuming a zero-cycle context switch LLF performs best, however implementation cost context, are prohibitive.
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IEEE PACT - A multithreaded Java microcontroller for thread-oriented real-time event-handling
1999 International Conference on Parallel Architectures and Compilation Techniques (Cat. No.PR00425), 1999Co-Authors: Uwe Brinkschulte, C Krakowski, J Kreuzinger, Th UngererAbstract:We propose a multithreaded Java microcontroller (called Komodo microcontroller) with a new hardware event handling mechanism that allows handling of simultaneous overlapping events with hard real-time requirements. Real-time Java threads are used as Interrupt Service threads (ISTs) instead of Interrupt Service routines (ISRs). Our proposed Komodo microcontroller supports multiple ISTs with zero-cycle context switching overhead. We evaluate the basic architectural attributes using real-time event parameters of an autonomous guided vehicle. When calculating the maximum vehicle speed without violating the real-time constraints, ISTs dominate ISRs by a speed increase of 28%.
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A multithreaded Java microcontroller for thread-oriented real-time event-handling
1999 International Conference on Parallel Architectures and Compilation Techniques (Cat. No.PR00425), 1999Co-Authors: Uwe Brinkschulte, C Krakowski, J Kreuzinger, Th UngererAbstract:We propose a multithreaded Java microcontroller (called Komodo microcontroller) with a new hardware event handling mechanism that allows handling of simultaneous overlapping events with hard real-time requirements. Real-time Java threads are used as Interrupt Service threads (ISTs) instead of Interrupt Service routines (ISRs). Our proposed Komodo microcontroller supports multiple ISTs with zero-cycle context switching overhead. We evaluate the basic architectural attributes using real-time event parameters of an autonomous guided vehicle. When calculating the maximum vehicle speed without violating the real-time constraints, ISTs dominate ISRs by a speed increase of 28%.
J Kreuzinger - One of the best experts on this subject based on the ideXlab platform.
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Interrupt Service threads a new approach to handle multiple hard real time events on a multithreaded microcontroller
2007Co-Authors: Uwe Brinkschulte, C Krakowski, J Kreuzinger, Th UngererAbstract:We propose a new event handling mechanism based on a multithreaded microcontroller, that allows efficient handling of simultaneous overlapping events with hard realtime requirements. Real-time threads are used as Interrupt Service threads (ISTs) instead of Interrupt Service routines (ISRs). ISTs are executed on a multithreaded microcontroller that supports multiple concurrently executing ISTs. Several thread priority schemes are managed in hardware, in particular, we propose a guaranteed percentage scheme where each real-time thread is assigned a rate of the full processing power. We show an analytical evaluation of the IST technique and the guaranteed percentage scheme using real-time requirements of an autonomous guided vehicle. The evaluations show that the ISR solution with the fixed priority preemptive scheme isn’t able to guarantee the specified deadlines, in contrast to the IST solution, that even offers a spare of 5%. Moreover, in our case guaranteed percentage scheduling offers an advantage over EDF scheduling, if not only deadlines, but also data rates must be met. When calculating the maximum vehicle speed without violating the real-time constraints ISTs dominate ISRs by a speed increase of 28%.
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RTCSA - Real-time scheduling on multithreaded processors
Proceedings Seventh International Conference on Real-Time Computing Systems and Applications, 2000Co-Authors: J Kreuzinger, Uwe Brinkschulte, A. Schulz, M. Pfeffer, T. Ungerer, C KrakowskiAbstract:This paper investigates real-time scheduling algorithms on upcoming multithreaded processors. As evaluation testbed we introduce a multithreaded processor kernel which is specifically designed as core processor of a micro-controller or system-on-a-chip. Handling of external real-time events is performed through multithreading. Real-time threads are used as Interrupt Service threads (ISTs) instead of Interrupt Service routines (ISRs). Our proposed micro-controller supports multiple ISTs with zero-cycle context switching overhead. We investigate the behavior of fixed priority preemptive, earliest deadline first, least laxity first and guaranteed percentage scheduling with respect to multithreaded processors. Our finding is that the strategies GP and LLF result in a good blending of instructions of different threads thus enabling a multithreaded processor to utilize latencies best. Assuming a zero-cycle context switch LLF performs best, however implementation cost context, are prohibitive.
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Real-time scheduling on multithreaded processors
Proceedings Seventh International Conference on Real-Time Computing Systems and Applications, 2000Co-Authors: J Kreuzinger, A. Schulz, M. Pfeffer, T. Ungerer, U. Brinkschulte, C KrakowskiAbstract:This paper investigates real-time scheduling algorithms on upcoming multithreaded processors. As evaluation testbed we introduce a multithreaded processor kernel which is specifically designed as core processor of a micro-controller or system-on-a-chip. Handling of external real-time events is performed through multithreading. Real-time threads are used as Interrupt Service threads (ISTs) instead of Interrupt Service routines (ISRs). Our proposed micro-controller supports multiple ISTs with zero-cycle context switching overhead. We investigate the behavior of fixed priority preemptive, earliest deadline first, least laxity first and guaranteed percentage scheduling with respect to multithreaded processors. Our finding is that the strategies GP and LLF result in a good blending of instructions of different threads thus enabling a multithreaded processor to utilize latencies best. Assuming a zero-cycle context switch LLF performs best, however implementation cost context, are prohibitive.
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IEEE PACT - A multithreaded Java microcontroller for thread-oriented real-time event-handling
1999 International Conference on Parallel Architectures and Compilation Techniques (Cat. No.PR00425), 1999Co-Authors: Uwe Brinkschulte, C Krakowski, J Kreuzinger, Th UngererAbstract:We propose a multithreaded Java microcontroller (called Komodo microcontroller) with a new hardware event handling mechanism that allows handling of simultaneous overlapping events with hard real-time requirements. Real-time Java threads are used as Interrupt Service threads (ISTs) instead of Interrupt Service routines (ISRs). Our proposed Komodo microcontroller supports multiple ISTs with zero-cycle context switching overhead. We evaluate the basic architectural attributes using real-time event parameters of an autonomous guided vehicle. When calculating the maximum vehicle speed without violating the real-time constraints, ISTs dominate ISRs by a speed increase of 28%.
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A multithreaded Java microcontroller for thread-oriented real-time event-handling
1999 International Conference on Parallel Architectures and Compilation Techniques (Cat. No.PR00425), 1999Co-Authors: Uwe Brinkschulte, C Krakowski, J Kreuzinger, Th UngererAbstract:We propose a multithreaded Java microcontroller (called Komodo microcontroller) with a new hardware event handling mechanism that allows handling of simultaneous overlapping events with hard real-time requirements. Real-time Java threads are used as Interrupt Service threads (ISTs) instead of Interrupt Service routines (ISRs). Our proposed Komodo microcontroller supports multiple ISTs with zero-cycle context switching overhead. We evaluate the basic architectural attributes using real-time event parameters of an autonomous guided vehicle. When calculating the maximum vehicle speed without violating the real-time constraints, ISTs dominate ISRs by a speed increase of 28%.
Th Ungerer - One of the best experts on this subject based on the ideXlab platform.
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Interrupt Service threads a new approach to handle multiple hard real time events on a multithreaded microcontroller
2007Co-Authors: Uwe Brinkschulte, C Krakowski, J Kreuzinger, Th UngererAbstract:We propose a new event handling mechanism based on a multithreaded microcontroller, that allows efficient handling of simultaneous overlapping events with hard realtime requirements. Real-time threads are used as Interrupt Service threads (ISTs) instead of Interrupt Service routines (ISRs). ISTs are executed on a multithreaded microcontroller that supports multiple concurrently executing ISTs. Several thread priority schemes are managed in hardware, in particular, we propose a guaranteed percentage scheme where each real-time thread is assigned a rate of the full processing power. We show an analytical evaluation of the IST technique and the guaranteed percentage scheme using real-time requirements of an autonomous guided vehicle. The evaluations show that the ISR solution with the fixed priority preemptive scheme isn’t able to guarantee the specified deadlines, in contrast to the IST solution, that even offers a spare of 5%. Moreover, in our case guaranteed percentage scheduling offers an advantage over EDF scheduling, if not only deadlines, but also data rates must be met. When calculating the maximum vehicle speed without violating the real-time constraints ISTs dominate ISRs by a speed increase of 28%.
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IEEE PACT - A multithreaded Java microcontroller for thread-oriented real-time event-handling
1999 International Conference on Parallel Architectures and Compilation Techniques (Cat. No.PR00425), 1999Co-Authors: Uwe Brinkschulte, C Krakowski, J Kreuzinger, Th UngererAbstract:We propose a multithreaded Java microcontroller (called Komodo microcontroller) with a new hardware event handling mechanism that allows handling of simultaneous overlapping events with hard real-time requirements. Real-time Java threads are used as Interrupt Service threads (ISTs) instead of Interrupt Service routines (ISRs). Our proposed Komodo microcontroller supports multiple ISTs with zero-cycle context switching overhead. We evaluate the basic architectural attributes using real-time event parameters of an autonomous guided vehicle. When calculating the maximum vehicle speed without violating the real-time constraints, ISTs dominate ISRs by a speed increase of 28%.
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A multithreaded Java microcontroller for thread-oriented real-time event-handling
1999 International Conference on Parallel Architectures and Compilation Techniques (Cat. No.PR00425), 1999Co-Authors: Uwe Brinkschulte, C Krakowski, J Kreuzinger, Th UngererAbstract:We propose a multithreaded Java microcontroller (called Komodo microcontroller) with a new hardware event handling mechanism that allows handling of simultaneous overlapping events with hard real-time requirements. Real-time Java threads are used as Interrupt Service threads (ISTs) instead of Interrupt Service routines (ISRs). Our proposed Komodo microcontroller supports multiple ISTs with zero-cycle context switching overhead. We evaluate the basic architectural attributes using real-time event parameters of an autonomous guided vehicle. When calculating the maximum vehicle speed without violating the real-time constraints, ISTs dominate ISRs by a speed increase of 28%.
Uwe Brinkschulte - One of the best experts on this subject based on the ideXlab platform.
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Interrupt Service threads a new approach to handle multiple hard real time events on a multithreaded microcontroller
2007Co-Authors: Uwe Brinkschulte, C Krakowski, J Kreuzinger, Th UngererAbstract:We propose a new event handling mechanism based on a multithreaded microcontroller, that allows efficient handling of simultaneous overlapping events with hard realtime requirements. Real-time threads are used as Interrupt Service threads (ISTs) instead of Interrupt Service routines (ISRs). ISTs are executed on a multithreaded microcontroller that supports multiple concurrently executing ISTs. Several thread priority schemes are managed in hardware, in particular, we propose a guaranteed percentage scheme where each real-time thread is assigned a rate of the full processing power. We show an analytical evaluation of the IST technique and the guaranteed percentage scheme using real-time requirements of an autonomous guided vehicle. The evaluations show that the ISR solution with the fixed priority preemptive scheme isn’t able to guarantee the specified deadlines, in contrast to the IST solution, that even offers a spare of 5%. Moreover, in our case guaranteed percentage scheduling offers an advantage over EDF scheduling, if not only deadlines, but also data rates must be met. When calculating the maximum vehicle speed without violating the real-time constraints ISTs dominate ISRs by a speed increase of 28%.
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RTCSA - Real-time scheduling on multithreaded processors
Proceedings Seventh International Conference on Real-Time Computing Systems and Applications, 2000Co-Authors: J Kreuzinger, Uwe Brinkschulte, A. Schulz, M. Pfeffer, T. Ungerer, C KrakowskiAbstract:This paper investigates real-time scheduling algorithms on upcoming multithreaded processors. As evaluation testbed we introduce a multithreaded processor kernel which is specifically designed as core processor of a micro-controller or system-on-a-chip. Handling of external real-time events is performed through multithreading. Real-time threads are used as Interrupt Service threads (ISTs) instead of Interrupt Service routines (ISRs). Our proposed micro-controller supports multiple ISTs with zero-cycle context switching overhead. We investigate the behavior of fixed priority preemptive, earliest deadline first, least laxity first and guaranteed percentage scheduling with respect to multithreaded processors. Our finding is that the strategies GP and LLF result in a good blending of instructions of different threads thus enabling a multithreaded processor to utilize latencies best. Assuming a zero-cycle context switch LLF performs best, however implementation cost context, are prohibitive.
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IEEE PACT - A multithreaded Java microcontroller for thread-oriented real-time event-handling
1999 International Conference on Parallel Architectures and Compilation Techniques (Cat. No.PR00425), 1999Co-Authors: Uwe Brinkschulte, C Krakowski, J Kreuzinger, Th UngererAbstract:We propose a multithreaded Java microcontroller (called Komodo microcontroller) with a new hardware event handling mechanism that allows handling of simultaneous overlapping events with hard real-time requirements. Real-time Java threads are used as Interrupt Service threads (ISTs) instead of Interrupt Service routines (ISRs). Our proposed Komodo microcontroller supports multiple ISTs with zero-cycle context switching overhead. We evaluate the basic architectural attributes using real-time event parameters of an autonomous guided vehicle. When calculating the maximum vehicle speed without violating the real-time constraints, ISTs dominate ISRs by a speed increase of 28%.
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A multithreaded Java microcontroller for thread-oriented real-time event-handling
1999 International Conference on Parallel Architectures and Compilation Techniques (Cat. No.PR00425), 1999Co-Authors: Uwe Brinkschulte, C Krakowski, J Kreuzinger, Th UngererAbstract:We propose a multithreaded Java microcontroller (called Komodo microcontroller) with a new hardware event handling mechanism that allows handling of simultaneous overlapping events with hard real-time requirements. Real-time Java threads are used as Interrupt Service threads (ISTs) instead of Interrupt Service routines (ISRs). Our proposed Komodo microcontroller supports multiple ISTs with zero-cycle context switching overhead. We evaluate the basic architectural attributes using real-time event parameters of an autonomous guided vehicle. When calculating the maximum vehicle speed without violating the real-time constraints, ISTs dominate ISRs by a speed increase of 28%.
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EUROMICRO - The Komodo project: thread-based event handling supported by a multithreaded Java microcontroller
Proceedings 25th EUROMICRO Conference. Informatics: Theory and Practice for the New Millennium, 1999Co-Authors: J Kreuzinger, Uwe Brinkschulte, T. Ungerer, R. Marston, C KrakowskiAbstract:The Komodo project concerns the handling of multiple real-time events by Java threads that are supported by a multithreaded Java microcontroller. The architecture of the processor core and resulting implications are considered. The use of thread-based event handling is introduced and explained in combination with an Automatic Guided Vehicle (AGV) application. The advantages of thread-based event handling over a normal Interrupt Service Routine (ISR) strategy are demonstrated by the development of the AGV example.
G. Guidi - One of the best experts on this subject based on the ideXlab platform.
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Non-preemptive Interrupt scheduling for safe reuse of legacy drivers in real-time systems
17th Euromicro Conference on Real-Time Systems (ECRTS'05), 2005Co-Authors: T. Facchinetti, G. Buttazzo, M. Marinoni, G. GuidiAbstract:Low-level support of peripheral devices is one of the most demanding activities in a real-time operating system. In fact, the rapid development of new interface boards causes a tremendous effort at the operating system level for writing and testing low-level drivers for supporting the new hardware. The possibility of reusing legacy drivers in real-time systems would offer the great advantage of keeping the rate of changes with a small programming effort. Since typical legacy drivers are written to execute in a non-preemptive fashion, a suitable operating system mechanism is needed to protect real-time application tasks from unpredictable bursty Interrupt requests. In this paper, we present a novel approach suitable for scheduling Interrupt Service routines. Main features of the method include: high priority of the handler, non preemptive execution, bandwidth reservation for the application tasks, and independence of the Interrupt Service policy from the scheduling policy adopted for the application tasks.
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ECRTS - Non-preemptive Interrupt scheduling for safe reuse of legacy drivers in real-time systems
17th Euromicro Conference on Real-Time Systems (ECRTS'05), 2005Co-Authors: T. Facchinetti, G. Buttazzo, M. Marinoni, G. GuidiAbstract:Low-level support of peripheral devices is one of the most demanding activities in a real-time operating system. In fact, the rapid development of new interface boards causes a tremendous effort at the operating system level for writing and testing low-level drivers for supporting the new hardware. The possibility of reusing legacy drivers in real-time systems would offer the great advantage of keeping the rate of changes with a small programming effort. Since typical legacy drivers are written to execute in a non-preemptive fashion, a suitable operating system mechanism is needed to protect real-time application tasks from unpredictable bursty Interrupt requests. In this paper, we present a novel approach suitable for scheduling Interrupt Service routines. Main features of the method include: high priority of the handler, non preemptive execution, bandwidth reservation for the application tasks, and independence of the Interrupt Service policy from the scheduling policy adopted for the application tasks.
