Ummmm when you care about I/O performance and your building anything of substance (something more than what nginx can do on it's own) why would you choose PHP? The security, fragility and un-maintainability alone are enough reasons to avoid it.
I'm not promoting php's use, just pointing out how benchmarking against a years old of anything is pretty useless. Which is another indicator the article was of low value and interest, providing no real, meaningful insight into those different languages.