[darcs-users] Re: [BK] upgrade will be needed

[Tomasz Zielonka]

On Mon, 21 Feb 2005 07:56:13 -0500, David Roundy
<droundy at abridgegame.org> > strace -e darcs ... 2> foo
> 
> gives
> 
> brk(0)                                  = 0x829e000
> brk(0)                                  = 0x829e000
> brk(0x82bf000)                          = 0x82bf000
> brk(0)                                  = 0x82bf000
> 
> I'm not sure what this means.  Since it's not a memory-intensive darcs
> call, I'm guessing this means we've used 0x82bf000 - 0x829e000  virtual
> memory, which probably just the RTS setting the heap size to its default
> value?
> 
> I've just glanced at the man page of sbrk.  I don't think the haskell RTS
> ever frees VM, so probably just one call of sbrk(0), or using strace ought
> to work.

GHC doesn't use brk() or sbrk() to allocate memory. It rather uses mmap()
for this. GHC's RTS "knows" the current size of Haskell heap. You can
run your program with options +RTS -sstderr -RTS - then it will show
you how much memory it used at the end. You can also use +RTS -? -RTS
to see other RTS options.

Best regards
Tomasz