DocumentCode :
1243865
Title :
Task clustering and scheduling for distributed memory parallel architectures
Author :
Palis, Michael A. ; Liou, Jing-Chiou ; Wei, David S L
Author_Institution :
Dept. of Electr. & Comput. Eng., New Jersey Inst. of Technol., Newark, NJ, USA
Volume :
7
Issue :
1
fYear :
1996
fDate :
1/1/1996 12:00:00 AM
Firstpage :
46
Lastpage :
55
Abstract :
This paper addresses the problem of scheduling parallel programs represented as directed acyclic task graphs for execution on distributed memory parallel architectures. Because of the high communication overhead in existing parallel machines, a crucial step in scheduling is task clustering, the process of coalescing fine grain tasks into single coarser ones so that the overall execution time is minimized. The task clustering problem is NP-hard, even when the number of processors is unbounded and task duplication is allowed. A simple greedy algorithm is presented for this problem which, for a task graph with arbitrary granularity, produces a schedule whose makespan is at most twice optimal. Indeed, the quality of the schedule improves as the granularity of the task graph becomes larger. For example, if the granularity is at least 1/2, the makespan of the schedule is at most 5/3 times optimal. For a task graph with n tasks and e inter-task communication constraints, the algorithm runs in O(n(n lg n+e)) time, which is n times faster than the currently best known algorithm for this problem. Similar algorithms are developed that produce: (1) optimal schedules for coarse grain graphs; (2) 2-optimal schedules for trees with no task duplication; and (3) optimal schedules for coarse grain trees with no task duplication
Keywords :
distributed memory systems; parallel architectures; processor scheduling; scheduling; NP-hard; approximation algorithms; directed acyclic task graphs; distributed memory; distributed memory architectures; greedy algorithm; parallel architectures; parallel machines; program task graph; task clustering problem; task granularity; task scheduling; Degradation; Memory architecture; Optimal scheduling; Parallel architectures; Parallel machines; Processor scheduling; Read-write memory; Scheduling algorithm; Senior members; Tree graphs;
fLanguage :
English
Journal_Title :
Parallel and Distributed Systems, IEEE Transactions on
Publisher :
ieee
ISSN :
1045-9219
Type :
jour
DOI :
10.1109/71.481597
Filename :
481597
Link To Document :
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