%0 Report %T Real-Time Scheduling of Tasks with Energy Constraints %+ Real time and interoperability (TRIO) %A Brito, Raul %Z Stage de DEA. Rapport de stage. %N A03-R-400 || brito03a %P 51 p %8 2003 %D 2003 %K portable and embedded systems %K real-time systems %K voltage scheduling %K energy minimization %K round-robin %K systèmes temps-réel %K ordonnancement de voltage %K minimization d'énergie %K dual-priority %K systèmes portables et embarqués %Z Computer Science [cs]/Other [cs.OH]Reports %X Energy consumption is a significant factor in the design of digital systems. The importance is even more notorious when contemplating portable and embedded systems, due to its operational dependancy of batteries. As processors are a preeminent source of energy consumption, novel techniques that fully exploit its hardware characteristics permit the improvement of energy gains. However, the costly trade-off is represented by the decrease of speed and consequent performance degredation. In this context, real-time systems provide the timeliness guarantees that allow to jointly consider energy reduction and minimum performance requirements. In this thesis, we address two scheduling policies, Round-Robin and Dual-Priority, for energy minimization purposes. Considering Round-Robin and Dual-Priority, the optimal discrete processor speed for scheduling job sets is discovered, founded in an efficient feasibility test, that is also proposed. Regarding Dual-Priority, the study of the mixed workload of soft and hard real-time tasks provided and opposing constraint of the energy minimization problem: the minimization of response times. Based in this ambivalence of the system, a design metric is defined. A derived importance concept of this metric is used in a methodology that supports engineering decisions in early stages of the real-time system design. A revised worst case response times formula for FPP is also presented, when tasks are scheduled with different processor speeds. %G English %L inria-00099680 %U https://inria.hal.science/inria-00099680 %~ CNRS %~ INRIA %~ INPL %~ INRIA-LORRAINE %~ LORIA2 %~ INRIA-NANCY-GRAND-EST %~ TESTALAIN1 %~ UNIV-LORRAINE %~ INRIA2 %~ LORIA %~ LARA