spring/spring — comment on commit b537941b94fc6103afba5db876b36737f524c9dd
File:  line 0
By zerver:

GCC seems to have thread safe function static variables unless -fno-threadsafe-statics compiler flag is set, which means this WILL produce a mutex and thus perform WORSE in spite of possible branch prediction advantages

So, please no more function static variables if the code is even slightly performance critical...