#698: GHC's internal memory allocator never releases memory back to the OS
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Reporter: guest | Owner: igloo
Type: bug | Status: new
Priority: low | Milestone: 6.12.3
Component: Runtime System | Version: 6.12.1
Keywords: | Difficulty: Moderate (less than a day)
Os: Unknown/Multiple | Testcase: N/A
Architecture: Unknown/Multiple | Failure: None/Unknown
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Changes (by tinlix):
* version: 6.4.1 => 6.12.1
Comment:
I have the following use case where it is important for the GC to free
memory.
I have a huge matrix file which needs to be multiplied with a vector. The
matrix is 100Gb in size, so it's not possible to use matlab to do it.
I used lazy string and thought I could use the readFile in
Data.ByteString.Lazy to read in the matrix one row at a time and do the
multiplication with the vector. The whole program just does a simple run
over the huge file. It turns out the program run out of memory as it goes
through the big file.
Finally I have to go back to C++/STL which enables me to write a program
that takes constant memory and solves the problem fine.
IMHO, this bug is serious. What a GC should provide, i.e. constant memory
consumption now becomes O(n). In a sense, this makes functions such as
readFile useless for serious use.
--
Ticket URL: <http://hackage.haskell.org/trac/ghc/ticket/698#comment:27>
GHC <http://www.haskell.org/ghc/>
The Glasgow Haskell Compiler
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