On the efficiency of localized work stealing

This paper investigates a variant of the work-stealing algorithm that we call the localized work-stealing algorithm. The intuition behind this variant is that because of locality, processors can benefit from working on their own work. Consequently, when a processor is free, it makes a steal attempt...

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Bibliographic Details
Main Authors: Suksompong, Warut, Leiserson, Charles E, Schardl, Tao Benjamin
Other Authors: Massachusetts Institute of Technology. Computer Science and Artificial Intelligence Laboratory
Format: Article
Language:en_US
Published: Elsevier 2019
Online Access:http://hdl.handle.net/1721.1/120140
https://orcid.org/0000-0001-6386-5552
https://orcid.org/0000-0003-0198-3283
Description
Summary:This paper investigates a variant of the work-stealing algorithm that we call the localized work-stealing algorithm. The intuition behind this variant is that because of locality, processors can benefit from working on their own work. Consequently, when a processor is free, it makes a steal attempt to get back its own work. We call this type of steal a steal-back. We show that the expected running time of the algorithm is T[subscript 1]/P + O(T[subscript ∞]P), and that under the “even distribution of free agents assumption”, the expected running time of the algorithm is T[subscript 1]/P + O(T[subscript ∞]lgP) . In addition, we obtain another running-time bound based on ratios between the sizes of serial tasks in the computation. If M denotes the maximum ratio between the largest and the smallest serial tasks of a processor after removing a total of O(P) serial tasks across all processors from consideration, then the expected running time of the algorithm is T[subscript 1]/ P+ O(T[subscript ∞]M). Keywords: Parallel algorithms; Multihreaded computation; Work stealing; Localization