[Haskell-cafe] Optimization again.

Donald Bruce Stewart dons at cse.unsw.edu.au
Thu Dec 14 09:31:00 EST 2006

> I profiled my program and found that residency looks pretty fixed but 
> program memory usage grows and eventually I get heap overflow (on 
> Windows) or heavy pagefile trashing (on Linux).
> When I turn on +RTS -c to use heap compaction I immediately get the 
> following:
> -----------------------------
> xxxx.exe: internal error: scavenge_mark_stack: unimplemented/strange 
> closure type 30 @ 03678268
>    Please report this as a bug to glasgow-haskell-bugs at haskell.org,
>    or http://www.sourceforge.net/projects/ghc/
> -----------------------------
> This already reported as a bug, but isn't fixed yet. The bug is right 
> here: http://cvs.haskell.org/trac/ghc/ticket/954
> It does appear with 6.4.1 too.

Can you produce this bug using ghc 6.6? If so, please submit a test case
so this can be reproduced and fixed. Either annotate the existing bug
(if you think its the same one), or create a new bug report:

> So I try as hard as I can to reduce the size of garbage produced. No 
> much luck so far.

Ok. I doubt anyone can help here though, unless you make the code
available :) Is it possible to put the code online? Is it available via

What does your profiling output look like? (The .prof file). What code
is doing the most allocation?

-- Don

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