The Python perf
module is a toolkit to write, run and analyze benchmarks.
- Simple API to run reliable benchmarks
- Automatically calibrate a benchmark for a time budget.
- Spawn multiple worker processes.
- Compute the mean and standard deviation.
- Detect if a benchmark result seems unstable.
- JSON format to store benchmark results.
- Support multiple units: seconds, bytes and integer.
To run a benchmark use the perf timeit
command (result written into
bench.json
):
$ python3 -m perf timeit '[1,2]*1000' -o bench.json ..................... Mean +- std dev: 4.22 us +- 0.08 us
Or write a benchmark script bench.py
:
#!/usr/bin/env python3
import perf
runner = perf.Runner()
runner.timeit(name="sort a sorted list",
stmt="sorted(s, key=f)",
setup="f = lambda x: x; s = list(range(1000))")
See the API docs for full details on the timeit
function and the
Runner
class. To run the script and dump the results into a file named
bench.json
:
$ python3 bench.py -o bench.json
To analyze benchmark results use the perf stats
command:
$ python3 -m perf stats bench.json Total duration: 29.2 sec Start date: 2016-10-21 03:14:19 End date: 2016-10-21 03:14:53 Raw value minimum: 177 ms Raw value maximum: 183 ms Number of calibration run: 1 Number of run with values: 40 Total number of run: 41 Number of warmup per run: 1 Number of value per run: 3 Loop iterations per value: 8 Total number of values: 120 Minimum: 22.1 ms Median +- MAD: 22.5 ms +- 0.1 ms Mean +- std dev: 22.5 ms +- 0.2 ms Maximum: 22.9 ms 0th percentile: 22.1 ms (-2% of the mean) -- minimum 5th percentile: 22.3 ms (-1% of the mean) 25th percentile: 22.4 ms (-1% of the mean) -- Q1 50th percentile: 22.5 ms (-0% of the mean) -- median 75th percentile: 22.7 ms (+1% of the mean) -- Q3 95th percentile: 22.9 ms (+2% of the mean) 100th percentile: 22.9 ms (+2% of the mean) -- maximum Number of outlier (out of 22.0 ms..23.0 ms): 0
There's also:
perf compare_to
command tests if a difference is significant. It supports comparison between multiple benchmark suites (made of multiple benchmarks)$ python3 -m perf compare_to py2.json py3.json --table +-----------+---------+------------------------------+ | Benchmark | py2 | py3 | +===========+=========+==============================+ | timeit | 4.70 us | 4.22 us: 1.11x faster (-10%) | +-----------+---------+------------------------------+
perf system tune
command to tune your system to run stable benchmarks.Automatically collect metadata on the computer and the benchmark: use the
perf metadata
command to display them, or theperf collect_metadata
command to manually collect them.--track-memory
and--tracemalloc
options to track the memory usage of a benchmark.
- perf documentation
- perf project homepage at GitHub (code, bugs)
- Download latest perf release at the Python Cheeseshop (PyPI)
Command to install perf on Python 3:
python3 -m pip install perf
perf supports Python 2.7 and Python 3. It is distributed under the MIT license.