This paper presents PIPQ, a strict and linearizable concurrent priority queue whose design differs from existing solutions in literature because it focuses on enabling parallelism of insert operations as opposed to accelerating delete-min operations, as traditionally done. In a nutshell, PIPQ’s structure includes two levels: the worker level and the leader level. The worker level provides per-thread data structures enabling fast and parallel insertions. The leader level contains the highest priority elements in the priority queue and can thus serve delete-min operations. Our evaluation, which includes an exploration of different data access patterns, operation mixes, runtime settings, and an integration into a graph-based application, shows that PIPQ outperforms competitors in a variety of cases, especially with insert-dominant workloads.
@InProceedings{grimes_et_al:LIPIcs.DISC.2025.35, author = {Grimes, Olivia and Hassan, Ahmed and Fatourou, Panagiota and Palmieri, Roberto}, title = {{PIPQ: Strict Insert-Optimized Concurrent Priority Queue}}, booktitle = {39th International Symposium on Distributed Computing (DISC 2025)}, pages = {35:1--35:23}, series = {Leibniz International Proceedings in Informatics (LIPIcs)}, ISBN = {978-3-95977-402-4}, ISSN = {1868-8969}, year = {2025}, volume = {356}, editor = {Kowalski, Dariusz R.}, publisher = {Schloss Dagstuhl -- Leibniz-Zentrum f{\"u}r Informatik}, address = {Dagstuhl, Germany}, URL = {https://drops.dagstuhl.de/entities/document/10.4230/LIPIcs.DISC.2025.35}, URN = {urn:nbn:de:0030-drops-248525}, doi = {10.4230/LIPIcs.DISC.2025.35}, annote = {Keywords: Priority Queue, Concurrent Data Structures, Synchronization} }