It's not hard to come up with a working green thread system, I've done that in a VM I'm developing for fun, but the crucial question is: Does it distribute the

It's not hard to come up with a working green thread system, I've done that in a VM I'm developing for fun, but the crucial question is: Does it distribute the fibers over native worker threads? That's my problem with most scheme implementations, they are great for single-threaded concurrency but require nasty hacks like Racket's 'places' for using all available CPU cores. The only fast multicore scheme I'm aware of is Chez, which has other problems, though. Does Guile do better than Racket with that respect?