[PROPOSAL] To retire autoconf for 4.1

[Volker Lendecke]

On Tue, May 21, 2013 at 10:40:31PM +1000, Andrew Bartlett wrote:
> If you are only changing those files, and have done a full compile in
> the recent past, then a simple 'make' will do just that.  Yes, you may
> not want to wait for it to link, but you can reduce that if you must by
> specifying a target, but once it is at that point you know that it does
> compile.  

Well, there is no such thing in waf as a quick compile. The
startup time alone is much longer than in autoconf. Also,
figuring out the right target name is something I can never
really figure out instantaneously.

> This is caused by the waf stages.  The difficultly with removing these
> is that we then must ensure our dependencies are absolutely perfect, as
> otherwise the builds may not be as reliable. 
> 
> Using ccache (with CC="ccache gcc" or the default installation on
> Fedora, which puts it in the path) is what I do to keep the compile
> delay under control.

Ah, another point: My default build is always with -O3 for
the warnings. When I have to use the debugger, I change the
Makefile to remove the -O3, recompile just the file in
question and I'm done. How do I do that with waf?

> This dependency calculation is essentially where the time goes.  A great
> deal of caching is done to keep this as short as possible, but the
> calculations must be done to ensure a correct build, every time. 
> 
> waf will never be as simple, nor as fast as a system without full
> dependency tracking, but a lot of effort was put in to make it as fast
> as it can be, within the constraint of always building correctly.  

Well, we have tons of CPUs. Can't we fork that into separate
processes?

Volker

-- 
SerNet GmbH, Bahnhofsallee 1b, 37081 Göttingen
phone: +49-551-370000-0, fax: +49-551-370000-9
AG Göttingen, HRB 2816, GF: Dr. Johannes Loxen
http://www.sernet.de, mailto:kontakt at sernet.de