[Haskell-cafe] 1TB vsize for all haskell processes?

[Michael Walker]

This was introduced here: https://ghc.haskell.org/trac/ghc/ticket/9706

Basically, if you can have a huge virtual address space (which you can
on a 64bit architecture) then you can simplify the memory management
logic.

On 17 October 2016 at 14:23, Michael Alan Dorman <mdorman at jaunder.io> wrote:
> Hey, haskell-cafe,
>
> I realize that this should not be a problem, but it is very strange to
> me that *every* haskell process on my system has a 1TB VSIZE.  If I sort
> my `ps auwx` output on vsize, the top of the list looks like:
>
>     mdorman   1208  0.0  0.1 1074011536 12500 ?    S    Oct14   0:04 /home/mdorman/.xmonad/xmonad-x86_64-linux
>     mdorman  21900  0.0  0.2 1074111408 19712 pts/1 Sl+ 09:06   0:00 cabal run melpa2nix -- --output melpa-generated.nix --melpa /home/mdorman/src/melpa --work /home/mdorman/src/emacs2nix/.workdir
>     mdorman   1363  0.0  0.1 1074383784 13052 ?    Sl   Oct14   1:14 /home/mdorman/.cache/taffybar/taffybar-linux-x86_64 +RTS -I0 -V0 --RTS --dyre-master-binary=/nix/store/6skvglp84w5xzqx8dxxydazk1zj8h2ih-taffybar-0.4.6/bin/taffybar
>     mdorman  21981  8.6  0.5 1076223012 42308 pts/1 Sl+ 09:06   0:19 /home/mdorman/src/emacs2nix/dist/build/melpa2nix/melpa2nix --output melpa-generated.nix --melpa /home/mdorman/src/melpa --work /home/mdorman/src/emacs2nix/.workdir
>
> Each of those haskell processes has a vsize 5 orders of magnitude more
> than their resident set size, whether it's the two I always have running
> (xmonad and taffybar), or in this case, cabal itself, as well as the
> compiled executable it's running.
>
> I've spent a reasonable amount of time attempting to google this, to no
> avail.  Is this perhaps a peculiarity of how GHC was built?  I'm running
> on nixos-unstable, using ghc-8.0.1---is there some compilation that we
> should or shouldn't be setting?
>
> Thanks for any guidance,
>
> Mike.
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-- 
Michael Walker (http://www.barrucadu.co.uk)