[Haskell-cafe] What could possibly be the reason of new GC-related problems after upgrading from ghc-7.6 to ghc-7.8.3 ?

[ducis]

Recently I revived one of my projects set aside a year ago. As I'm an archlinux user, the ghc version has now inevitably become 7.8.3.  Unfortunatly, the program starts to somehow have very bad GC performance (less than 50% productivity) . While I don't have the statistics of the older versions I'm pretty sure the current version has become visually less responsive. And if the user performs a series of actions in quick succession, the heap is not garbage collected in time and overflows. If the user performs the same actions with longer pauses then everything is fine.  The GC seems to have become more loose in 7.8.
There is quite a large underdocumented pile of code so I don't think posting it here would help.  But can anyone give me a hint about what could be the reason?
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