Hi,
My understanding is that currently neither the Immix or Boehm support multithreading in Scala Native. Multithreaded immix is being worked on right now and is part of the holdup for the topic/multithreading branch (Google summer of code Java/Posix threads implementation) as well as some sort of memory barrier support in the runtime as well but I’m not too knowledgeable in this area. These are probably due in the 0.4.0 release.
I think enabling Boehm would be welcome. If you are interested in Scala Native, I would suggest hanging out on the gitter channel. https://gitter.im/scala-native/scala-native Denys is the expert and designer and main builder of Scala Native. Tons of cool stuff to work on.