Running PyPy in a virtualenv

This is a quick guide to running your [python/django] project on PyPy, the fast JIT-based Python interpreter (and optionally benchmark re: cPython)

Install PyPy

Follow the clearly detailed instructions in:

For example, for 32-bit linux I used:

$ wget
$ tar xvf pypy-1.8-linux.tar.bz2

This will create a folder named pypy-1.8, which matches Python 2.7.2:

$ ./pypy-1.8/bin/pypy --version
Python 2.7.2 (0e28b379d8b3, Feb 09 2012, 19:41:19)
[PyPy 1.8.0 with GCC 4.4.3]

Create your virtual environment

Install distribute and pip for pypy:

NOTE: These instructions no longer work. is a domain for sale.

$ # wget  ## OBSOLETE
$ wget
$ ./pypy-1.8/bin/pypy
$ ./pypy-1.8/bin/pypy

Make sure you have at least virtualenv 1.6, else it won’t work with PyPy:

$ virtualenv --version

Install virtualenvwrapper, and create a new virtual environment for your projectx:

$ ./pypy-1.8/bin/pip install virtualenvwrapper
$ mkvirtualenv --no-site-packages --distribute --python=/path/to/pypy-1.8/bin/pypy projectx-pypy
$ python --version
Python 2.7.2 (0e28b379d8b3, Feb 09 2012, 19:41:19)
[PyPy 1.8.0 with GCC 4.4.3]

Now we have a virtual environment named projectx-pypy based on pypy that we can use as just any other virtualenv.

Setup your project

Install your project’s requirements as usual:

$ workon projectx-pypy
$ pip install -r requirements.txt -r test-requirements.txt

Benchmark if desired

Now I can easily compare timings between cPython and PyPy. I created another identical virtualenv based on cPython (2.7.2) and run the same tests (one testcase replicated 100000 times using nose test generators, just to have something time consuming and CPU-intensive).


$ workon projectx-pypy
$ nosetests
Ran 100000 tests in 8.624s


$ workon projectx
$ nosetests
Ran 100000 tests in 38.180s

Of course this is not a representative sample, but just a simple test. In this one case, PyPy takes approximately 20% the execution time of cPython. Not bad, huh?

The PyPy people have more comprehensive benchmarks in their speed center.

So give PyPy a try, and share your results.

3 thoughts on “Running PyPy in a virtualenv

  1. Thanks for these instructions. Searched quite a bit on google but did not find instructions that were as clear.

    • Thanks, you are totally right. These instructions are three years old, so I’m sure that there are much better ways to install PyPy by now. At the time of writing, it was not that trivial.

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