The program will start to ask you for a ''number of runs''. By convention on newer machines (1Ghz>=1GHz), the number of runs used is about '''~100000000''' (100 million). There are no rules or standards about how many runs it should be. Some people calculate the number of runs through "Dhrystone run time erros" (way too advanced); what matters is the consistency of the result. For consistent results, dhrystone is executed more than 5 times with same values for number of runs.