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SOSP '87 Proceedings of the eleventh ACM Symposium on Operating systems principles
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IEEE Transactions on Software Engineering
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Journal of the ACM (JACM)
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Journal of the ACM (JACM)
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STOC '02 Proceedings of the thiry-fourth annual ACM symposium on Theory of computing
Dynamic- and Static-priority Scheduling of Recurring Real-time Tasks
Real-Time Systems
FUNDAMENTAL DESIGN PROBLEMS OF DISTRIBUTED SYSTEMS FOR THE HARD-REAL-TIME ENVIRONMENT
FUNDAMENTAL DESIGN PROBLEMS OF DISTRIBUTED SYSTEMS FOR THE HARD-REAL-TIME ENVIRONMENT
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OPODIS'07 Proceedings of the 11th international conference on Principles of distributed systems
Global deadline-monotonic scheduling of arbitrary-deadline sporadic task systems
OPODIS'07 Proceedings of the 11th international conference on Principles of distributed systems
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ACM Transactions on Architecture and Code Optimization (TACO) - HIPEAC Papers
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Optimal online scheduling algorithms are known for sporadic task systems scheduled upon a single processor. Additionally, optimal online scheduling algorithms are also known for restricted subclasses of sporadic task systems upon an identical multiprocessor platform. The research reported in this article addresses the question of existence of optimal online multiprocessor scheduling algorithms for general sporadic task systems. Our main result is a proof of the impossibility of optimal online scheduling for sporadic task systems upon a system comprised of two or more processors. The result is shown by finding a sporadic task system that is feasible on a multiprocessor platform that cannot be correctly scheduled by any possible online, deterministic scheduling algorithm. Since the sporadic task model is a subclass of many more general real-time task models, the nonexistence of optimal scheduling algorithms for the sporadic task systems implies nonexistence for any model which generalizes the sporadic task model.