Unlike the so-called "Perl threads" (which are not actually real threads but only the windows process emulation (see section of same name for more details) ported to UNIX, and as such act as processes), Coro provides a full shared address space, which makes communication between threads very easy. And coro threads are fast, too: disabling the Windows process emulation code in your perl and using Coro can easily result in a two to four times speed increase for your programs.