I spent almost all day trying to find and fix really strange bug in one of our server-side applications written on Perl. And as I’ve figured out later, there is huge problem in Perl core libraries or, even, in interpreter.
Problem is following. If you are trying to use “threads” module with “Thread::Semaphore” module like it is mentioned in official Perl documentation (perlthrtut), you’ll get 4kb memory leak on every $semaphore->up call. So, simple test-case like following would cause huge memory leaks (100 Mbytes per second on my test server):