Currently Julia handles parallelism on its own: you use the parallel primitives or higher-level functions provided by the language, not an mpi, and run over multiple processes using either "julia -p <N>" (on a single machine) or "Julia -hostfile <host list>" (on a cluster). The Julia interpreter does the networking itself in the background: currently I'm pretty sure this tunnels over ssh.

I rather like Julia's parallel syntax, but I'd really prefer that the inter-host communication by done via MPI on the back end for performance. Something to hack at if I ever get time...