A method and apparatus for determining a stack distance histogram for running software. The method may include receiving a plurality of memory references each including a corresponding address. The method may also include performing a first hash function and a second hash function on each received address. In addition, the method may include selectively storing an indication representative of each corresponding address in a hash table dependent upon results of the first hash function and the second hash function. A stack distance may then be determined based upon contents of the hash table.