Python .perf_counter_ns()

.perf_counter_ns() is a function from the time module that returns a high-resolution timer value in nanoseconds as an integer.

Syntax

time.perf_counter_ns()

Parameters:

The .perf_counter_ns() function takes no arguments.

Return value:

Returns the value of a high-resolution performance counter in nanoseconds as an integer.

Example 1

In this example, .perf_counter_ns() from the time module is used to measure elapsed time for a block of code by taking timestamps before and after execution and calculating the difference:

import time

start = time.perf_counter_ns() # start timer
end = time.perf_counter_ns()   # end timer

print("Elapsed:", end - start, "nanoseconds")

Copy to clipboard
Copy to clipboard

A sample output for this code is:

Elapsed: 800 nanoseconds

Copy to clipboard
Copy to clipboard

Example 2

This example shows how to use .perf_counter_ns() to benchmark even small tasks very precisely:

import time
import random

# Create a random list of numbers
numbers = [random.randint(1, 1000000) for _ in range(100000)]

# Start timer
start = time.perf_counter_ns()

# Code we want to measure
numbers.sort()

# End timer
end = time.perf_counter_ns()

# Calculate elapsed time
elapsed_ns = end - start
print(f"Sorting took {elapsed_ns} nanoseconds ({elapsed_ns / 1e6:.3f} ms)")

Copy to clipboard
Copy to clipboard

A sample output of this code is:

Sorting took 20045800 nanoseconds (20.046 ms)

Copy to clipboard
Copy to clipboard

This code generates a large list of random numbers, sorts it, and calculates the elapsed time by subtracting the start timestamp from the end timestamp, giving a precise measurement in nanoseconds (and milliseconds for readability).