py.test fixture for benchmarking code
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scorphus and ionelmc Require pytest>=3.6
Changes introduced by pytest 4.0 are breaking ones and require at least
3.6. Ref #129

Thanks, @ionelmc!
Latest commit e6d9b63 Nov 23, 2018



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A py.test fixture for benchmarking code. It will group the tests into rounds that are calibrated to the chosen timer. See calibration and FAQ.

  • Free software: BSD license


pip install pytest-benchmark


For latest release:

For master branch (may include documentation fixes):


But first, a prologue:

This plugin tightly integrates into pytest. To use this effectively you should know a thing or two about pytest first. Take a look at the introductory material or watch talks.

Few notes:

  • This plugin benchmarks functions and only that. If you want to measure block of code or whole programs you will need to write a wrapper function.
  • In a test you can only benchmark one function. If you want to benchmark many functions write more tests or use parametrization <>.
  • To run the benchmarks you simply use py.test to run your "tests". The plugin will automatically do the benchmarking and generate a result table. Run py.test --help for more details.

This plugin provides a benchmark fixture. This fixture is a callable object that will benchmark any function passed to it.


def something(duration=0.000001):
    Function that needs some serious benchmarking.
    # You may return anything you want, like the result of a computation
    return 123

def test_my_stuff(benchmark):
    # benchmark something
    result = benchmark(something)

    # Extra code, to verify that the run completed correctly.
    # Sometimes you may want to check the result, fast functions
    # are no good if they return incorrect results :-)
    assert result == 123

You can also pass extra arguments:

def test_my_stuff(benchmark):
    benchmark(time.sleep, 0.02)

Or even keyword arguments:

def test_my_stuff(benchmark):
    benchmark(time.sleep, duration=0.02)

Another pattern seen in the wild, that is not recommended for micro-benchmarks (very fast code) but may be convenient:

def test_my_stuff(benchmark):
    def something():  # unnecessary function call

A better way is to just benchmark the final function:

def test_my_stuff(benchmark):
    benchmark(time.sleep, 0.000001)  # way more accurate results!

If you need to do fine control over how the benchmark is run (like a setup function, exact control of iterations and rounds) there's a special mode - pedantic:

def my_special_setup():

def test_with_setup(benchmark):
    benchmark.pedantic(something, setup=my_special_setup, args=(1, 2, 3), kwargs={'foo': 'bar'}, iterations=10, rounds=100)


Normal run:

Screenshot of py.test summary

Compare mode (--benchmark-compare):

Screenshot of py.test summary in compare mode

Histogram (--benchmark-histogram):

Histogram sample

Also, it has nice tooltips.


To run the all tests run: