You need to use PyPy to run this. To get started, using a recent virtualenv (1.6.1 or newer), virtualenvwrapper, and a recent PyPy. PyPy versions correspond to jitviewer tags, so pypy-1.9 tag in jitviewer means it works with pypy 1.9. On Mac OSX you will also need to install binutils, to make objdump available. To create a virtualenv (note that mkvirtualenv only accepts absolute paths): mkvirtualenv --python=/path/to/pypy pypy-viewer Now install the dependencies: pip install -r requirements.txt or python setup.py develop It also requires pypy to be importable (as in source code), you can do this by setting your ``PYTHONPATH`` enviroment variable. Make sure that this source code is (roughly) the same version as the binary pypy that produced the log file. Finally, run it: jitviewer.py log.pypylog where log.pypylog is a logfile generated by PYPYLOG=jit-log-opt,jit-backend:log.pypylog pypy <args>. An example log file comes with a checkout.