On Mon, Feb 6, 2012 at 5:31 PM, Norbert Zeh
I did a very superficial test of the source of the problem, and in my case it seems to be the decoration module that adds tabs above all my windows. Without decoration, I can open 30+ terminals and focus switch feels almost snappy and certainly does not trigger the endless loop. The moment I turn any form of decoration on, focus switching, at least with many windows, starts to feel sluggish. Are you using window decorations?
I am not entirely certain what inside the decoration module would create such massive delays - the CPU usage on one of my cores goes up to 50% when I'm in the endless loop. I'm not too keen to dig into it because this module is a monster, but it may simply be necessary.
Why does this issue - 'Tabs is horrible for performance!' - sound so very similar... Perhaps it's time to add a warning to the Tabs haddocks to the effect it is known to hurt performance. -- gwern http://www.gwern.net