Hi,

I'm not sure if it is the best place to put this issue. I'm working on an IPython notebook with a lot of objects loaded: len(gc.get_objects()) is about 5M. Everything works fine until an inline plot is drawn. Drawing itself is fast, but then there is a delay (5-10s). The delay is caused by gc.collect() executed by matplotlib: https://github.com/matplotlib/matplotlib/blob/master/lib/matplotlib/_pylab_helpers.py#L93. After the first plot the notebook becomes slow for all cells (even without inline plots). When interrupting the kernel (for cells without plots) I can see the same gc.collect() happening inside matplotlib.

As a workaround I'm monkey-patching gc.collect to be no-op, but this is clearly a hack.

It is gc.collect() call in matplotlib code that makes things slow, but why does IPython notebook need to call matplotlib code for cells without charts?