time.perf_counter() vs time.process_time()

The time module in python3 is used to provide various time-related functions.

We will discuss the major differences and use cases of the time.perf_counter() and time.process_time().

time.perf_counter(): float

Returns the value (in fractional seconds) of a performance counter, i.e. a clock with the highest available resolution to measure a short duration. It does include time elapsed during sleep and is system-wide. The reference point of the returned value is undefined, so that only the difference between the results of two calls is valid.

We can use perf_counter_ns() to avoid the precision loss caused by the float type.

Here is an example of how to use time.perf_counter():

import time
def my_function():
    # Do some work here

start = time.perf_counter()
my_function()
end = time.perf_counter()
elapsed_time = end - start

print(f"Elapsed time for my_function(): {elapsed_time}")

time.process_time(): float

Return the value (in fractional seconds) of the sum of the system and user CPU time of the current process. It does not include time elapsed during sleep. It is process-wide by definition. The reference point of the returned value is undefined, so that only the difference between the results of two calls is valid.

Use process_time_ns() to avoid the precision loss caused by the float type.

Here is an example of how to use time.process_time():

import time
def factorial(n):
    # Do some work here

start_time = time.process_time()
factorial(10)
end_time = time.process_time()
elapsed_time = end_time - start_time

print("Elapsed time:", elapsed_time)

Example

import time

def pc():
    start = time.perf_counter()
    time.sleep(1)
    print(time.perf_counter()-start)

def pt():
    start = time.process_time()
    time.sleep(1)
    print(time.process_time()-start)

pc()  # 0.99872320449432
pt()  # 0.0

Major Differences

References

• https://docs.python.org/3/library/time.html

• https://stackoverflow.com/questions/52222002/what-is-the-difference-between-time-perf-counter-and-time-process-time