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.
The author used a query along the lines of:
Except for the language they wanted to win, which was basically written like: Which, of course, resulted in it their favorite being the clear winner.