[IPython-User] IPython 0.11.x "sluggishness" in pylab mode

[Wes McKinney]

Something I've noticed using the git HEAD IPython in pylab mode-- if I
leave it for a minute or two and use another application (say, emacs
or Chrome), then come back to the terminal and start typing something,
it will consistently "hang" momentarily (maybe 200ms to a second or
more) before the console input appears on screen. This didn't happen
in IPython 0.10.x so I was curious what could be causing it. This is
on 64-bit Ubuntu 10.04 with EPD 6.2.2.

Anyone else notice this? It only seems to happen in Pylab mode so I
assume it's some kind of concurrency / threading issue.

The way I'm reproducing this:

start IPython in pylab mode (WXAgg backend default)
wait 60 seconds
start typing something, problem present
%gui (to disable gui backends)
wait 60 seconds
start typing something, no lag / hanging
%gui wx
wait 60 seconds
start typing something, problem present

Thanks,
Wes