[Nix-dev] contribute patches and support of AIX platform

[Lluís Batlle i Rossell]

On Tue, Mar 15, 2011 at 04:31:09PM -0400, Olexiy Buyanskyy wrote:
> All,
> 
> On Tue, Mar 15, 2011 at 9:04 AM, Olexiy Buyanskyy <olexiyb at gmail.com> wrote:
> I found solution here
> http://publib.boulder.ibm.com/tividd/td/ITAME/GC32-0846-00/en_US/HTML/am39_perftune11.htm
> I had to set to complete nix-env execution without std::bad_alloc
> export LDR_CNTRL=MAXDATA=0x2000000
> This means nix-env requires at least 512Mb to parse all nix files
> And I also see really bad performance
> $ time nix-env -qaf nixpkgs '*'
> real    2m3.254s
> user    0m35.016s
> sys     0m0.306s

With those user/sys times, it looks like your machine is swapping a lot (using
disk pages), or your filesystem delivers the file contents very slow. What about
the amount of RAM dedicated to the nix-env process? Enough?

What do you think that time consumption comes from?

Eelco Dolstra once reported in the mailing list the evaluation times of some
recent nix release, but I can't find it. For my system:

1st run)
real    0m37.702s
user    0m1.416s
sys     0m0.515s

2nd run)  (filesystem cache playing a heavier role)
real    0m2.093s
user    0m1.270s
sys     0m0.340s

It may also happen that libgc or libgcc or libstdc++ (exceptions specially) are
not very well tuned for your system.

That's for linux. Maybe the nixpkgs evaluation in your system is very different,
but I don't think so. So, an interesting problem to solve. :)

Regards,
Lluís.