MinecraftForge/MinecraftForge — pull request #339 by Uristqwerty (2012-12-25 01:52:01+00:00)
Title: Fix for ListenerList performance issue.

Force parent ListenerListInsts to rebuild.

Without this change, it is possible (and, in fact, nearly guaranteed) for lists to rebuild endlessly if a parent list is marked as needing a rebuild but never actually read. This change forces the parent list(s) to rebuild as well, resulting in a significant performance increase and smoother framerate due to greatly reduced GC activity.

I don't have exact numbers, but before the change my framerate frequently dropped to single digits, with it it usually remained above 10.