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

[Jeff Johnson]

On Jun 22, 2010, at 12:18 PM, Marc Weber wrote:

> Hi Jeff.
> 
> Did you ever set both -l and -j options to very different values?
> If so for what reason? I did'nt find a use case yet which is worth
> paying attention to because we want to find settings which works best in
> most cases.
> 

Nope not tried -lN. Its the "portability" and the "automagic" and
the "Inquiring minds want to ..." heuristics for filling in the
make invocation "lazily/recursively substituted strings" template of
	make %{?_smp_mflags}
that litters all RPM spec file "recipes" everywhere for years.

WYSIWYG! Wotta concept

"Oh gee its a macro, let's fiddle, shall we?"

are what I hear about. The incidence of bug reports is
quite predictable, there's a wave of suggestions for better
make option insturmentation as each generational cohort tries to
learn how to "hack" ... nothing wrong with cohorts at all.

> Which kind of breakage have you seen in your career due to using
> parallel builds and build systems not supporting it?
> 

The breakage I've seen in my career is when _REALLY_ smart
people (you included) waste a whole lotta time discussing
what is ultimately passing an option to an executable, an
act we all do every day, no fuss, no muss.

> How does rpm try to protect against failures?
> 

Build recipes are left to build mommas and package monkeys in RPM methodology.

(aside)
I lust the pleasant simplicity of Nix "build recipes" over the
"If I only had a grammar ..." eye-scratchy macro+script+markup+haveityourownway
cesspool that RPM spec files have become.

Let's say I'm shopping a better mouse trap ;-)

Please excuse my scarcasm, I've gone over "make -jN ..." ground
so many times in RPM its embarrasingly painful.

And I'd like to see Nix get it right. The heuristics (with -lN etc)
are quite a bit more intelligently engineered than anything I've ever
heard before.

But ultimately, its just options passed to make(1), just deal with it
and get on to more interesting tasks please.

73 de Jeff