The power of choice in priority scheduling
| Autor: | Justin Kopinsky, Jerry Li, Dan Alistarh, Giorgi Nadiradze |
|---|---|
| Jazyk: | angličtina |
| Rok vydání: | 2017 |
| Předmět: |
FOS: Computer and information sciences
Mathematical optimization Concurrent data structure Computer science Rank (computer programming) 0102 computer and information sciences 02 engineering and technology 01 natural sciences Randomized algorithm Priority inheritance Computer Science - Distributed Parallel and Cluster Computing 010201 computation theory & mathematics 020204 information systems Computer Science - Data Structures and Algorithms 0202 electrical engineering electronic engineering information engineering Double-ended priority queue Data Structures and Algorithms (cs.DS) Distributed Parallel and Cluster Computing (cs.DC) Priority queue Time complexity Queue |
| Zdroj: | Proceedings of the ACM Symposium on Principles of Distributed Computing (PODC '17) PODC |
| Popis: | Consider the following random process: we are given $n$ queues, into which elements of increasing labels are inserted uniformly at random. To remove an element, we pick two queues at random, and remove the element of lower label (higher priority) among the two. The cost of a removal is the rank of the label removed, among labels still present in any of the queues, that is, the distance from the optimal choice at each step. Variants of this strategy are prevalent in state-of-the-art concurrent priority queue implementations. Nonetheless, it is not known whether such implementations provide any rank guarantees, even in a sequential model. We answer this question, showing that this strategy provides surprisingly strong guarantees: Although the single-choice process, where we always insert and remove from a single randomly chosen queue, has degrading cost, going to infinity as we increase the number of steps, in the two choice process, the expected rank of a removed element is $O( n )$ while the expected worst-case cost is $O( n \log n )$. These bounds are tight, and hold irrespective of the number of steps for which we run the process. The argument is based on a new technical connection between "heavily loaded" balls-into-bins processes and priority scheduling. Our analytic results inspire a new concurrent priority queue implementation, which improves upon the state of the art in terms of practical performance. |
| Databáze: | OpenAIRE |
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