Cilk does indeed sync on function return. You can also manually call 'cilk_sync'. I do think that Cilk’s approach is better (more in line with “make error states unrepresentable”, which I’m a big fan of), but Julia’s approach seems to be more in line with their overall goal of giving the programmer as much control as possible. Not sure if that’s a good thing or not, but as said above... we’ll find out soon!