A Scalable, Portable, and Memory-Efficient Lock-Free FIFO Queue

Official repository: https://github.com/rusnikola/lfqueue

• Publications

  wCQ: A Fast Wait-Free Queue with Bounded Memory Usage.
  In Proceedings of the 34th ACM Symposium on Parallelism in Algorithms
  and Architectures (SPAA'22). Philadelphia, PA, USA.
  

  Paper

  A Scalable, Portable, and Memory-Efficient Lock-Free FIFO Queue.
  In Proceedings of the 33rd International Symposium on DIStributed
  Computing (DISC'19). Budapest, Hungary.
  

  Paper

• Source code license

  Copyright (c) 2019, 2021 Ruslan Nikolaev. All Rights Reserved.

  The SCQ/SCQD/SCQ2/NCQ/wCQ code is dual-licensed under 2-Clause BSD and MIT.

• Description

  The benchmark code is in the "benchmark" directory,
  which is forked from the original WFQUEUE's benchmark
  available [here](https://github.com/chaoran/fast-wait-free-queue).
  For usage, see its original README file in "benchmark".
  
  Additional queues were implemented. See the description below for
  details.
  
  Both GCC and LLVM should be supported. Older versions may lack
  support for lfring\_cas2.h and wfring\_cas2.h and/or have
  suboptimal performance. We have tested the code with
  GCC 8.3.0+ and LLVM 7.0.1+.
  

• CAS

  An implementation of the FAA test using CAS emulation (based on
  the original FAA test).
  

• NCQ

  A naive implementation of the ring buffer. The implementation is in
  lfring\_naive.h.
  

• SCQ

  This is a "bare-bones" SCQ which simply implements *enqueue* and *dequeue*
  (all platforms). The implementation is in lfring\_cas1.h.
  

• SCQD

  This is a version which stores pointers as data entries through indirection
  (all platforms). The implementation is in lfring\_cas1.h.
  

• SCQ2

  This is a version which stores pointers through double-width CAS
  (certain platforms such as x86-64). The implementation is in lfring\_cas2.h.
  

• wCQ

  An implementation of a wait-free version of SCQ, which uses double-width
  CAS (certain platforms such as x86-64). The implementation is in
  wfring\_cas2.h.