How to get time (milisecond) of a python IO execution

[Tal Bar-Or]

Hi All

i am trying to test measure some IO execution in milliseconds , but bit confuse about best method achive that under windows 7
i am using following code but not sure if its best or correct way since i have two different results, which one should i take as results
and which is best way
please advice
Thanks

code exec results 
100000000 loops, best of 3: 0.00925 usec per loop
3.827947176762156


run code
    import timeit ,time
    import datetime
    import os


    def main():
       
       
        os.path.getsize("c:/video-2011-09-09-09-32-29.mp4")
       

    if __name__ == '__main__':

        t = timeit.Timer('main()')

        print (t.timeit(1))