Getting somewhat closer to releasing a new version of #swad. I now improved the functionality to execute something on a different worker thread: Use an in-memory queue, providing a #lockfree version. This gives me a consistent reliable throughput of 3000 requests/s (with outliers up to 4500 r/s) at an average response time of 350 - 400 ms (with TLS enabled). For waking up worker threads, I implemented different backends as well: kqueue, eventfd and event-ports, the fallback is still a self-pipe.
So, #portability here really means implement lots of different flavors of the same thing.
Looking at these startup logs, you can see that #kqueue (#FreeBSD and other BSDs) is really a "jack of all trades", being used for "everything" if available (and that's pretty awesome, it means one single #syscall per event loop iteration in the generic case). #illumos' (#Solaris) #eventports come somewhat close (but need a lot more syscalls as there's no "batch registering" and certain event types need to be re-registered every time they fired), they just can't do signals, but illumos offers Linux-compatible signalfd. Looking at #Linux, there's a "special case fd" for everything. 
Plus #epoll also needs one syscall for each event to be registered. The "generic #POSIX" case without any of these interfaces is just added for completeness 
