You have already been linked the performance tip link once: http://julia.readthedocs.org/en/latest/manual/performance-tips/
It even explicitly says: "Unexpected memory allocation is almost always a sign of some problem with your code, usually a problem with type-stability. Consequently, in addition to the allocation itself, it’s very likely that the code generated for your function is far from optimal. Take such indications seriously and follow the advice below." When you start with something new, it is generally appreciated if you try take some time to read the documentation. Explaining the same thing to everyone is an O(N) effort while writing a good documentation explaining it is O(1).
