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Online Parallel Scheduling of Non-uniform Tasks: Trading Failures for Energy

Fernández Anta, Antonio and Georgiou, Chryssis and Kowalski, Dariusz R. and Zavou, Elli (2013) Online Parallel Scheduling of Non-uniform Tasks: Trading Failures for Energy. In: The 19th International Symposium on Fundamentals of Computation Theory (FCT 2013), 19 - 21 August 2013, Liverpool, England, UK.

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Consider a system in which tasks of different execution times arrive continuously and have to be executed by a set of processors that are prone to crashes and restarts. In this paper we model and study the impact of parallelism and failures on the competitiveness of such an online system. In a fault-free environment, a simple Longest-in-System scheduling policy, enhanced by a redundancy-avoidance mechanism, guarantees optimality in a long-term execution. In the presence of failures though, scheduling becomes a much more challenging task. In particular, no parallel deterministic algorithm can be competitive against an offline optimal solution, even with one single processor and tasks of only two different execution times. We find that when additional energy is provided to the system in the form of processor speedup, the situation changes. Specifically, we identify thresholds on the speedup under which such competitiveness cannot be achieved by any deterministic algorithm, and above which competitive algorithms exist. Finally, we propose algorithms that achieve small bounded competitive ratios when the speedup is over the threshold.

Item Type: Conference or Workshop Papers (Paper)
Subjects: Q Science > Q Science (General)
Q Science > QA Mathematics > QA75 Electronic computers. Computer science
T Technology > T Technology (General)
T Technology > TA Engineering (General). Civil engineering (General)
T Technology > TK Electrical engineering. Electronics Nuclear engineering
Divisions: Faculty of Engineering, Science and Mathematics > School of Electronics and Computer Science
Depositing User: Elli Zavou
Date Deposited: 28 Jun 2013 11:02
Last Modified: 03 Mar 2014 08:59

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