Comment by candybar

I keep hearing about this, but do people really rewrite performance-critical parts of their web apps in C? Even if it happens to be part of some third-party library? And maintain a fork? What if that performance-critical part is dependent on other parts in a non-trivial way? It seems that an unanticipated replacement of some core functionality with a C library may involve a major rewrite and most Ruby teams may not have the expertise to do a good job maintaining a C code base any way.