How to measure time in numba.jit function?

Question

I want to convert a conventional loop into a numba.jit function and measure time of its processes internally. I tried using time module but it doesn't seem to be compatible with numba.

Code:

from numba import jit, jitclass
import time

@jit(nopython=True)
def harmonic_load_flow_func():
    time1 = time.perf_counter()
    calc = 0
    for x in range(1000000):
        calc += x
    print('time: {}'.format(time.perf_counter() - time1))

if __name__ == '__main__':
    for count in range(10):
        harmonic_load_flow_func()

Output:

C:\Users\Artur\Anaconda\python.exe C:/Users/Artur/Desktop/RL_framework/help_functions/test.py
Traceback (most recent call last):
  File "C:/Users/Artur/Desktop/RL_framework/help_functions/test.py", line 14, in <module>
    harmonic_load_flow_func()
  File "C:\Users\Artur\Anaconda\lib\site-packages\numba\core\dispatcher.py", line 401, in _compile_for_args
    error_rewrite(e, 'typing')
  File "C:\Users\Artur\Anaconda\lib\site-packages\numba\core\dispatcher.py", line 344, in error_rewrite
    reraise(type(e), e, None)
  File "C:\Users\Artur\Anaconda\lib\site-packages\numba\core\utils.py", line 80, in reraise
    raise value.with_traceback(tb)
numba.core.errors.TypingError: Failed in nopython mode pipeline (step: nopython frontend)
Unknown attribute 'perf_counter' of type Module(<module 'time' (built-in)>)

File "test.py", line 6:
def harmonic_load_flow_func():
    time1 = time.perf_counter()
    ^

[1] During: typing of get attribute at C:/Users/Artur/Desktop/RL_framework/help_functions/test.py (6)

File "test.py", line 6:
def harmonic_load_flow_func():
    time1 = time.perf_counter()
    ^


Process finished with exit code 1

score 8 · Accepted Answer · answered Jun 17 '20 at 08:37

8

Yeah, it does not support the time module.

You can either use objmode() or wrap the whole call with plain python function and measure:

from numba import jit, objmode
import time

@jit(nopython=True)
def harmonic_load_flow_func_time_inside():
    with objmode(time1='f8'):
        time1 = time.perf_counter()
    calc = 0
    for x in range(1000000):
        calc += x
    with objmode():
        print('time: {}'.format(time.perf_counter() - time1))

@jit(nopython=True)
def harmonic_load_flow_func():
    calc = 0
    for x in range(1000000):
        calc += x

def main_time_inside():
    for _ in range(10):
        harmonic_load_flow_func_time_inside()

def main_time_outside():   
    for _ in range(10):
        time1 = time.perf_counter()
        harmonic_load_flow_func()
        print('time: {}'.format(time.perf_counter() - time1))

if __name__ == '__main__':
    print("measuring time inside the function")
    main_time_inside()
    print("measuring time from outside")
    main_time_outside()

answered Jun 17 '20 at 08:37

LiMar

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1

May I know what `time1='f8'` does? Is it the amount of float decimals? – Artur Müller Romanov Jun 17 '20 at 08:45
1

And another question: would this be possible inside an njit function? – Artur Müller Romanov Jun 17 '20 at 08:46
1

`'f8'` is type notation as in https://numba.pydata.org/numba-doc/dev/reference/types.html#numbers . It's needed to return the variable from objmode() python context to jitted one, because the variable is used later. – LiMar Jun 17 '20 at 08:48
1

`njit` is just an alias to `jit(nopython=True)`. See here: https://numba.pydata.org/numba-doc/latest/user/performance-tips.html#no-python-mode-vs-object-mode – LiMar Jun 17 '20 at 08:51
Thanks you for your help! – Artur Müller Romanov Jun 17 '20 at 08:59
@ArturMüllerRomanov please consider awarding the bounty ... – LiMar Jun 17 '20 at 09:21
bounty can be awarded 24h after it was set up. I'll do it as soon as it's possible – Artur Müller Romanov Jun 17 '20 at 09:32
Good answer! But these for-loops get completely optimized by numba. You're benchmarking a noop operation. Try something like `calc = 1.; for x in range(1000000): calc *= 1.001` to get real computation going. – Antony Hatchkins Nov 25 '20 at 22:14

How to measure time in numba.jit function?

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