I'm not sure that sentence makes much sense though since the O/S is responsible for creating processes after all. There's an inherent overhead in the POSIX proc

I'm not sure that sentence makes much sense though since the O/S is responsible for creating processes after all. There's an inherent overhead in the POSIX process model; but there's also overhead in the kind of manual memory management needed in support for evented I/O considering typical mixed web server workloads.