[Nix-dev] second revision of NUM_CORES patch series

[Eelco Dolstra]

Hi,

On 06/13/2010 11:49 PM, Marc Weber wrote:

> Nix:
> 
>   pass NIX_MAX_PARALLELIZATION and NIX_TARGET_LOAD to the builder.
>   This is currently only used the default builder running make.
>   See patch to NixPkgs

I'm not convinced that this is a good idea.  I'm kind of afraid that this opens
the way for all sorts of flags to influence a build externally (say, a flag to
change the GCC optimization flags).

>   - setup.sh: Refactor running make because -j and -l with opt-out possibility are added

As I said before I'm much more comfortable with opt-in.  Your Nixpkgs commit
turns off parallelism for a bunch of packages, which immediately prompts the
question how you know that these are sufficient.  There might be many more
packages with Makefiles that are not parallelism-safe, but you just haven't
noticed yet.

Also, capitalized (or strangely mixed) variable names such as "NUM_CORES" and
"NO_PARALLEL_BUILD_buildPhase" in Nix expressions are ugly.  It's also
inconsistent to disable parallel builds by setting NUM_CORES to 1, but to
disable them in one phase by setting "NO_PARALLEL_BUILD_..." to true.

-- 
Eelco Dolstra | http://www.st.ewi.tudelft.nl/~dolstra/