Installing airspeed velocity

airspeed velocity is known to work on Linux, Mac OS-X, and Windows. It is known to work with Python 3.7 and higher. It works also with PyPy.

airspeed velocity is a standard Python package, and the latest released version may be installed in the standard way from PyPI:

pip install asv

The development version can be installed by cloning the source repository and running pip install . inside it, or by pip install git+

The requirements should be automatically installed. If they aren’t installed automatically, for example due to networking restrictions, the python requirements are as noted in the pyproject.toml.

For managing the environments, one of the following packages is required:

  • libmambapy, which is typically part of mamba. In this case conda must be present too.

  • virtualenv, which is required since venv is not compatible with other versions of Python.

  • An anaconda or miniconda installation, with the conda command available on your path.


libmambapy is the fastest for situations where non-pythonic dependencies are required. Anaconda or miniconda is slower but still preferred if the project involves a lot of compiled C/C++ extensions and are available in the conda repository, since conda will be able to fetch precompiled binaries for these dependencies in many cases. Using virtualenv, dependencies without precompiled wheels usually have to be compiled every time the environments are set up.

Optional optimization

If your project being benchmarked contains C, C++, Objective-C or Cython, consider installing ccache. ccache is a compiler cache that speeds up compilation time when the same objects are repeatedly compiled. In airspeed velocity, the project being benchmarked is recompiled at many different points in its history, often with only minor changes to the source code, so ccache can help speed up the total benchmarking time considerably.

Running the self-tests

The self tests are based on pytest. If you don’t have it installed, and you have a connection to the Internet, it will be installed automatically.

To run airspeed velocity’s self tests: