You'd probably have to move more to a CSP type concurrency versus threads if you were to leverage multicore machines. Erlang doesn't allow individual processes to share memory with each other, but Erlang is undoubtedly a great platform to build apps in that make use of concurrency (depending on use case). Something tells me that the use cases for which one would use Mirage for would be those more likely to use Erlang-type concurrency semantics versus highly multithreaded code using shared memory.