You might want to take a look at the timeit
module:
http://docs.python.org/library/timeit.html
or the profile
module:
http://docs.python.org/library/profile.html
There are some additionally some nice tutorials here:
http://www.doughellmann.com/PyMOTW/profile/index.html
http://www.doughellmann.com/PyMOTW/timeit/index.html
And the time
module also might come in handy, although I prefer the later two recommendations for benchmarking and profiling code performance:
http://docs.python.org/library/time.html