For fairness sake, I with the author would note the version of the C compiler they used. Otherwise saying PyPy is faster than C is like saying "my 2010 Toyota Prius is faster than a car in a carefully crafted example".

Sorry to sound like a language curmudgeon, but if you're going to make a claim that language x is faster than language y you're treading on thin ice. Languages in and of themselves don't have a whole lot of grounding in reality (especially Python; C has some closer analogues to the machine). That is to say that the devil is always in the details, or in this case the implementation of the compiler. Though my guess is the author of this blog post may not have intended for this small post to be flung across various nerd news sources to invoke the ire of language zealots everywhere.

The fact that the compiler can't inline across file boundaries (which is why PyPy is 'faster' in this case), I would think, is not a limitation of the C language, but rather a limitation of a C compiler (which I assume is GCC).