Fresh install of gnuradio-18.104.22.168 via PyBOMBS-2.0.1 on Ubuntu 15.10
When trying to run CrtlPort Performance Monitor on a fresh 22.214.171.124 install, I got errors about missing pygraphviz.
sudo apt-get python-pygraphviz
solved it for me. The supposedly equivalent
sudo apt-get install graphviz
[sudo apt-get install graphviz-dev libgraphviz-dev]
pip install pygraphviz
threw a bunch of errors and claimed to be successful, but didn't work. So beware PyPI, in this case.