Running out of memory profiling a script

I'm trying to profile a script but functiontrace keeps gobbling up all my memory and crashing. I'm doing:

$ cd /tmp
$ git clone --depth 1 https://github.com/googlefonts/noto-source/
$ git clone https://github.com/madig/noto-amalgamated.git
$ cd noto-amalgamated && python3 -m venv venv && . venv/bin/activate && pip install glyphsLib==6.0.0b4 functiontrace
$ functiontrace amalgamate-noto.py

Is there anything I can do?