A Scalable, Correct Time-Stamped Stack

Concurrent data-structures, such as stacks, queues, and deques, often implicitly enforce a total order over elements in their underlying memory layout. However, much of this order is unnecessary: linearizability only requires that elements are ordered if the insert methods ran in sequence. We propose a new approach which uses timestamping to avoid unnecessary ordering. Pairs of elements can be left unordered (represented by unordered timestamps) if their associated insert operations ran concurrently, and order imposed as necessary by the eventual remove operations. We realise our approach in a new non-blocking datastructure, the TS (timestamped) stack. In experiments on x86, the TS stack outperforms and outscales all its competitors – for example, it outperforms the elimination-backoff stack by factor of two. In our approach, more concurrency translates into less ordering, giving less-contended removal and thus higher performance and scalability. Despite this, the TS stack is linea...

• Type: Journal
• Year: 2015
• Where: POPL
• Authors: Mike Dodds, Andreas Haas, Christoph M. Kirsch
• Keywords: POPL 2015, Programming Languages