Parallelism for Common Lisp
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Latest commit 9c11f40 Jul 20, 2016


lparallel is a library for parallel programming in Common Lisp, featuring

  • a simple model of task submission with receiving queue
  • constructs for expressing fine-grained parallelism
  • asynchronous condition handling across thread boundaries
  • parallel versions of map, reduce, sort, remove, and many others
  • promises, futures, and delayed evaluation constructs
  • computation trees for parallelizing interconnected tasks
  • bounded and unbounded FIFO queues
  • high and low priority tasks
  • task killing by category
  • integrated timeouts

See for documentation and examples.


lparallel should run on any Common Lisp implementation supported by bordeaux-threads. The following implementations successfully pass the test suite:

  • ABCL
  • Allegro
  • Clozure
  • LispWorks
  • SBCL

To run tests, load lparallel-test.asd and call (lparallel-test:execute).

To run benchmarks, load lparallel-bench.asd and call (lparallel-bench:execute N) where N is the number of worker threads.


James M. Lawrence