For malebolgia, look into <https://github.com/Araq/malebolgia/blob/ed698c2e6ecb84291ad70cd172c61b43ef6f56a6/src/malebolgia/paralgos.nim#L8> maybe ? You can pass bulk argument with it to avoid creating too many thread for low computation overhead.
Araq covered the topic in his video : <https://www.youtube.com/watch?v=MIITSTQok-4> but I don't think the doc has been updated yet
