Key response in IPython gets very slow

[oxon]

Found the same topic in 2017.

Incredible slowdown when trying to use pyROOT in ipython (MacOS)

I am trying to use pyROOT in ipython but I have two issues: First, it takes 30 seconds to import (I have timed it). Secondly, after a minute or after having called import ROOT in ipython, input becomes so delayed as to be totally unusable. There’s a lag on the order of several seconds between pressing a key and the ipython session responding. I’m on ROOT 6.10.08 and ipython version 5.4.0, with python2.7. I could put up with the 30s import but the several second lag is genuinely unusable. I…

I don’t know why it is still happening in 2020.