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Journal of Applied Mathematics and Decision Sciences
Volume 2005 (2005), Issue 4, Pages 225-240

Partially clairvoyant scheduling for aggregate constraints

Lane Department of Computer Science and Electrical Engineering (LDCSEE), West Virginia University, Morgantown 26506, WV, USA

Received 10 February 2004

Copyright © 2005 Hindawi Publishing Corporation. This is an open access article distributed under the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited.


The problem of partially clairvoyant scheduling is concerned with checking whether an ordered set of jobs, having nonconstant execution times and subject to a collection of imposed constraints, has a partially clairvoyant schedule. Variability of execution times of jobs and nontrivial relationships constraining their executions, are typical features of real-time systems. A partially clairvoyant scheduler parameterizes the schedule, in that the start time of a job in a sequence can depend upon the execution times of jobs that precede it, in the sequence. In real-time scheduling, parameterization of the schedule plays an important role in extending the flexibility of the scheduler, particularly in the presence of variable execution times. It has been shown that the existence of partially clairvoyant schedules can be determined in polynomial time, when the constraints are restricted to be “standard,” that is, relative timing constraints. In this paper, we extend the class of constraints for which partially clairvoyant schedules can be determined efficiently, to include aggregate constraints. Aggregate constraints form a strict superset of standard constraints and can be used to model performance metrics.