Effective multicore computing requires to make efficient usage of the computational resources on a chip. Off-line mapping and scheduling can be applied to improve the performance, but classical approaches require considerable a-priori knowledge of the target application. In a practical setting, precise information is often unavailable; one can then resort to approximate time and resource usage figures, but this usually requires to make conservative assumptions. The issue is further stressed if real-time guarantees must be provided. We tackle predictable and efficient non-preemptive scheduling of multi-task applications in the presence of duration uncertainty. Hard real-time guarantees are provided with limited idle time insertion, by exploiting a hybrid off-line/on-line technique known as Precedence Constraint Posting (PCP). Our approach does not require probability distributions to be specified, relying instead on simple and cheaper-to-obtain information (bounds, average values). The method has been tested on synthetic applications/platforms and compared with an off-line optimized Fixed Priority Scheduling (FPS) approach and a pure on-line FIFO scheduler; the results are very promising, as the PCP schedules exhibit good stability and improved average execution time (14% on average, up to 30% versus FPS and up to 40% versus the FIFO scheduler).

Robust Scheduling of Task Graphs under Execution Time Uncertainty / Lombardi M. ; Milano M. ; Benini L.. - In: IEEE TRANSACTIONS ON COMPUTERS. - ISSN 0018-9340. - ELETTRONICO. - 62:1(2013), pp. 98-111. [10.1109/TC.2011.203]

Robust Scheduling of Task Graphs under Execution Time Uncertainty

LOMBARDI, MICHELE;MILANO, MICHELA;BENINI, LUCA
2013

Abstract

Effective multicore computing requires to make efficient usage of the computational resources on a chip. Off-line mapping and scheduling can be applied to improve the performance, but classical approaches require considerable a-priori knowledge of the target application. In a practical setting, precise information is often unavailable; one can then resort to approximate time and resource usage figures, but this usually requires to make conservative assumptions. The issue is further stressed if real-time guarantees must be provided. We tackle predictable and efficient non-preemptive scheduling of multi-task applications in the presence of duration uncertainty. Hard real-time guarantees are provided with limited idle time insertion, by exploiting a hybrid off-line/on-line technique known as Precedence Constraint Posting (PCP). Our approach does not require probability distributions to be specified, relying instead on simple and cheaper-to-obtain information (bounds, average values). The method has been tested on synthetic applications/platforms and compared with an off-line optimized Fixed Priority Scheduling (FPS) approach and a pure on-line FIFO scheduler; the results are very promising, as the PCP schedules exhibit good stability and improved average execution time (14% on average, up to 30% versus FPS and up to 40% versus the FIFO scheduler).
2013
Robust Scheduling of Task Graphs under Execution Time Uncertainty / Lombardi M. ; Milano M. ; Benini L.. - In: IEEE TRANSACTIONS ON COMPUTERS. - ISSN 0018-9340. - ELETTRONICO. - 62:1(2013), pp. 98-111. [10.1109/TC.2011.203]
Lombardi M. ; Milano M. ; Benini L.
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Utilizza questo identificativo per citare o creare un link a questo documento: https://hdl.handle.net/11585/108917
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