CLI is very slow (on first run)

[m-roberts]

pi@pi-top:~ $ time pi-top devices hub --name-only
Matplotlib is building the font cache; this may take a moment.
pi-top [4]

real	0m18.715s
user	0m7.799s
sys	0m2.242s

pi@pi-top:~ $ time pi-top devices hub --name-only
pi-top [4]

real	0m1.761s
user	0m1.682s
sys	0m0.711s

I am not sure why the first run does this, as I can't see an actual call to matplotlib in this command.