1. A data processing apparatus comprising: trace logic for monitoring behaviour of a portion of said data processing apparatus; and prediction logic operable to provide at least one prediction as to at least one step of said behaviour of said portion of said data processing apparatus; wherein said trace logic is operable to: monitor behaviour of said portion of said data processing apparatus; determine from said monitored behaviour whether or not said at least one prediction is correct; and output a prediction indicator indicating whether or not said at least one prediction is correct.