Help-Optimal and Language-Portable Lock-Free Concurrent Data Structures
Paper i proceeding, 2016

Helping is a widely used technique to guarantee lock-freedom in many concurrent data structures. An optimized helping strategy improves the overall performance of a lock-free algorithm. In this paper, we propose help-optimality, which essentially implies that no operation step is accounted for exclusive helping in the lock-free synchronization of concurrent operations. To describe the concept, we revisit the designs of a lock-free linked-list and a lock-free binary search tree and present improved algorithms. Our algorithms employ atomic single-word compare-and-swap (CAS) primitives and are linearizable. We design the algorithms without using any language/platformspecific mechanism. Specifically, we use neither bit-stealing froma pointer nor runtime type introspection of objects. Thus, our algorithms are language-portable. Further, to optimize the amortized number of steps per operation, if a CAS execution tomodify a shared pointer fails, we obtain a fresh set of thread-local variables without restarting an operation from scratch. We use several micro-benchmarks in both C/C++ and Java to validate the efficiency of our algorithms against existing state-of-the-art. The experiments show that the algorithms are scalable. Our implementations perform on a par with highly optimizedones and in many cases yield 10%-50% higher throughput.

Help

Language-portable

Concurrent data structure

Lock-free

Linearizability

Binary search tree

Help-optimal

Linked-list

Författare

Bapi Chatterjee

Chalmers, Data- och informationsteknik, Nätverk och system

Ivan Walulya

Chalmers, Data- och informationsteknik, Nätverk och system

Philippas Tsigas

Chalmers, Data- och informationsteknik, Nätverk och system

45th International Conference on Parallel Processing (ICPP), 2016

0190-3918 (ISSN)

Vol. 2016 september 360-369

Ämneskategorier

Data- och informationsvetenskap

DOI

10.1109/ICPP.2016.48

ISBN

978-150902823-8