标准库, 可以用来简单的计时
import timeit
import time
time_start = timeit.default_timer()
time.sleep(1)
time_diff = timeit.default_timer() - time_start
print 'time used: %ds=%.1fmin'%(time_diff, time_diff/60.0)
for more detailed reference, see https://docs.python.org/2/library/timeit.html