[Nix-dev] Why Nix-0.16 so hungry on ressources (mem + cpu) ?

[Lluís Batlle i Rossell]

On Sun, Oct 30, 2011 at 09:34:50PM +0100, Vladimír Čunát wrote:
> Hi.
> 
> On 26 October 2011 23:47, Paul Dufresne <dufresnep at gmail.com> wrote:
> > It seems that it need to evaluate all the nix expressions in the
> > unstable packages.While doing this, top reports that it eats about 72%
> > of my memory (256Mb Physical + 256Mb virtual).
> 
> "/var/run/current-system/sw/bin/time -f %M nix-env -i hello --dry-run"
> reports using 1.3 GB RAM (!)
> "/var/run/current-system/sw/bin/time -f %M nix-env -iA hello
> --dry-run" reports 56 MB RAM

On the sheevaplug, 512MB of physical RAM, and the same amount of swap:
7.88user 0.71system 0:09.86elapsed 87%CPU (0avgtext+0avgdata 617568maxresident)k
0inputs+0outputs (4major+41841minor)pagefaults 0swaps

I think Eelco thinks there is a bug in 'time' about the remort of memory,
showing something 4-times bigger or so on some systems. Maybe we have something
bad about page-size in headers/kernel?

For the cpu.. I'm quite happy for the result.

The same command, without swap, works much worse. :)

Regards,
Lluís.