pi@raspberrypi:~/netperf $ sudo pip install matplotlib
Looking in indexes: https://pypi.org/simple, https://www.piwheels.org/simple
Requirement already satisfied: matplotlib in /usr/local/lib/python2.7/dist-packages (2.2.4)
Requirement already satisfied: subprocess32 in /usr/local/lib/python2.7/dist-packages (from matplotlib) (3.5.4)
Requirement already satisfied: cycler>=0.10 in /usr/local/lib/python2.7/dist-packages (from matplotlib) (0.10.0)
Requirement already satisfied: python-dateutil>=2.1 in /usr/local/lib/python2.7/dist-packages (from matplotlib) (2.8.0)
Requirement already satisfied: kiwisolver>=1.0.1 in /usr/local/lib/python2.7/dist-packages (from matplotlib) (1.1.0)
Requirement already satisfied: numpy>=1.7.1 in /usr/lib/python2.7/dist-packages (from matplotlib) (1.16.2)
Requirement already satisfied: pyparsing!=2.0.4,!=2.1.2,!=2.1.6,>=2.0.1 in /usr/local/lib/python2.7/dist-packages (from matplotlib) (2.4.2)
Requirement already satisfied: backports.functools-lru-cache in /usr/local/lib/python2.7/dist-packages (from matplotlib) (1.5)
Requirement already satisfied: six>=1.10 in /usr/lib/python2.7/dist-packages (from matplotlib) (1.12.0)
Requirement already satisfied: pytz in /usr/local/lib/python2.7/dist-packages (from matplotlib) (2019.2)
Requirement already satisfied: setuptools in /usr/lib/python2.7/dist-packages (from kiwisolver>=1.0.1->matplotlib) (40.8.0)
pi@raspberrypi:~/netperf $
pi@raspberrypi:~/netperf $ flent rrul -p all_scaled -l 60 -H netperf.bufferbloat.net -t "Download and upload test" -o flent.png
Started Flent 1.3.0 using Python 2.7.16.
Starting rrul test. Expected run time: 70 seconds.
Data file written to ./rrul-2019-09-04T223321.866440.Download_and_upload_test.flent.gz.
ERROR: Unable to plot -- matplotlib is missing! Please install it if you want plots.