> Our servers are under continuing heavy load due to having launched recently and the site being on the front page of HN. This is causing poor performance and undefined behavior.

How is that possible? As I understand, undefined behaviour is either there when you compile, or it isn't (it is a function of the source code). So if the undefined behaviour is a function of traffic intensity, I assume you compile different C code base when you have high load. I never heard about something like this before.