[Nix-dev] Re: Parallel building support, 1st attempt

[Peter Simons]

Hi Jeff,

 >> 1) Nix-env provides the environment variable $NIX_BUILD_CORES. The
 >>    default value is 1, which is equivalent to building with
 >>    parallelism disabled.
 >
 > Specify the means to set the envvar please, like what the inputs to
 > the heuristic are. There are most definitely "portability" issues
 > associated with discovering #CORES and the details should be spelled
 > out.

could you please take a look at the patches? There is quite a bit of
documentation and commentary. If that question is still unclear to you
after reading the diffs I posted, please don't hesitate to ask for
clarification.


 >> 3) The packages gcc, glibc, gmp, mpfr, coreutils, perl, git, and qt4
 >>    now define $enableParallelBuilding.
 >
 > You are likely to make better forward progress with "opt-in" rather
 > than "opt-out" logic.

I am sorry, but there seems to be a misunderstanding. The implementation
does use opt-in.

Take care,
Peter