--- res: bibo_abstract: - High-performance concurrent priority queues are essential for applications such as task scheduling and discrete event simulation. Unfortunately, even the best performing implementations do not scale past a number of threads in the single digits. This is because of the sequential bottleneck in accessing the elements at the head of the queue in order to perform a DeleteMin operation. In this paper, we present the SprayList, a scalable priority queue with relaxed ordering semantics. Starting from a non-blocking SkipList, the main innovation behind our design is that the DeleteMin operations avoid a sequential bottleneck by "spraying" themselves onto the head of the SkipList list in a coordinated fashion. The spraying is implemented using a carefully designed random walk, so that DeleteMin returns an element among the first O(plog3p) in the list, with high probability, where p is the number of threads. We prove that the running time of a DeleteMin operation is O(log3p), with high probability, independent of the size of the list. Our experiments show that the relaxed semantics allow the data structure to scale for high thread counts, comparable to a classic unordered SkipList. Furthermore, we observe that, for reasonably parallel workloads, the scalability benefits of relaxation considerably outweigh the additional work due to out-of-order execution.@eng bibo_authorlist: - foaf_Person: foaf_givenName: Dan-Adrian foaf_name: Alistarh, Dan-Adrian foaf_surname: Alistarh foaf_workInfoHomepage: http://www.librecat.org/personId=4A899BFC-F248-11E8-B48F-1D18A9856A87 orcid: 0000-0003-3650-940X - foaf_Person: foaf_givenName: Justin foaf_name: Kopinsky, Justin foaf_surname: Kopinsky - foaf_Person: foaf_givenName: Jerry foaf_name: Li, Jerry foaf_surname: Li - foaf_Person: foaf_givenName: Nir foaf_name: Shavit, Nir foaf_surname: Shavit bibo_doi: 10.1145/2688500.2688523 bibo_volume: 2015-January dct_date: 2015^xs_gYear dct_language: eng dct_publisher: ACM@ dct_title: 'The SprayList: A scalable relaxed priority queue@' ...