According to one aspect, a method includes determining whether at least one memory storage unit in a first stage of a multi-stage array is available for use by a first counter associated with the first stage, and allocating the at least one memory storage unit for use by the first counter when the at least one memory storage unit is available. When the at least one memory storage unit is not available for use by the first counter, the method includes identifying a second counter stored in a first location in the first stage, the first location including a first memory storage unit and a second memory storage unit, and moving the second counter to a second stage of the multi-stage array, storing a pointer to the second stage in the first memory storage unit, and allocating the second memory storage unit to the first counter.