Get time of execution of a block of code in Python 2.7
I would like to measure the time elapsed to evaluate a block of code in a Python program, possibly separating between user cpu time, system cpu time and elapsed time.
I know the timeit
module, but I have many self-written functions and it is not very easy
to pass them in the setup process.
I would rather have something that could be used like:
#up to here I have done something....
start_counting() #or whatever command used to mark that I want to measure
#the time elapsed in the next rows
# code I want to evaluate
user,system,elapsed = stop_counting() #or whatever command says:
#stop the timer and return the times
The user and system CPU times are not essential (though I would like to measure them), but for the elapsed time I would like to be able to do something like this, rather than using complicated commands or modules.
To get the elapsed time in seconds, you can use timeit.default_timer()
:
import timeit
start_time = timeit.default_timer()
# code you want to evaluate
elapsed = timeit.default_timer() - start_time
timeit.default_timer()
is used instead of time.time()
or time.clock()
because it will choose the timing function that has the higher resolution for any platform.
I always use a decorator to do some extra work for a existing function, including to get the execution time. It is pythonic and simple.
import time
def time_usage(func):
def wrapper(*args, **kwargs):
beg_ts = time.time()
retval = func(*args, **kwargs)
end_ts = time.time()
print("elapsed time: %f" % (end_ts - beg_ts))
return retval
return wrapper
@time_usage
def test():
for i in xrange(0, 10000):
pass
if __name__ == "__main__":
test()
You can achieve this through the Context Manager, for example:
from contextlib import contextmanager
import time
import logging
@contextmanager
def _log_time_usage(prefix=""):
'''log the time usage in a code block
prefix: the prefix text to show
'''
start = time.time()
try:
yield
finally:
end = time.time()
elapsed_seconds = float("%.2f" % (end - start))
logging.debug('%s: elapsed seconds: %s', prefix, elapsed_seconds)
use example:
with _log_time_usage("sleep 1: "):
time.sleep(1)