*Result*: Approximating Real-Time Scheduling on Identical Machines.

Title:
Approximating Real-Time Scheduling on Identical Machines.
Source:
LATIN 2014: Theoretical Informatics; 2014, p550-561, 12p
Database:
Complementary Index

*Further Information*

*We study the problem of assigning <italic>n</italic> tasks to <italic>m</italic> identical parallel machines in the real-time scheduling setting, where each task recurrently releases jobs that must be completed by their deadlines. The goal is to find a partition of the task set over the machines such that each job that is released by a task can meet its deadline. Since this problem is co-NP-hard, the focus is on finding <italic>α</italic>-approximation algorithms in the resource augmentation setting, i.e., finding a feasible partition on machines running at speed <italic>α</italic> ≥ 1, if some feasible partition exists on unit-speed machines. Recently, Chen and Chakraborty gave a polynomial-time approximation scheme if the ratio of the largest to the smallest relative deadline of the tasks, <italic>λ</italic>, is bounded by a constant. However, their algorithm has a super-exponential dependence on <italic>λ</italic> and hence does not extend to larger values of <italic>λ</italic>. Our main contribution is to design an approximation scheme with a substantially improved running-time dependence on <italic>λ</italic>. In particular, our algorithm depends exponentially on log<italic>λ</italic> and hence has quasi-polynomial running time even if <italic>λ</italic> is polynomially bounded. This improvement is based on exploiting various structural properties of approximate demand bound functions in different ways, which might be of independent interest. [ABSTRACT FROM AUTHOR]

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