24.16.7. gem5 Python 3 build
Python 3 support was mostly added in 2019 Q3 at arounda347a1a68b8a6e370334be3a1d2d66675891e0f1 but remained buggy for some time afterwards.
In an Ubuntu 18.04 host where python is python2 by default, build with Python 3 instead with:
./build-gem5 --gem5-build-id python3 -- PYTHON_CONFIG=python3-config
Python 3 is then automatically used when running if you use that build.