Instead of Stdlib.Queue you can use Eio.Stream, which is thread-safe (and will take care of waking sleeping threads when data becomes available). The README sh

Instead of Stdlib.Queue you can use Eio.Stream, which is thread-safe (and will take care of waking sleeping threads when data becomes available). The README shows an example of a pool of workers pulling jobs from an Eio.Stream: https://github.com/ocaml-multicore/eio#example-a-worker-pool https://github.com/ocaml-multicore/eio#example-a-worker-pool We're still exploring what APIs to provide for this kind of thing, and in particular how to unify domainslib and eio.