Re: Building cvs emacs on a dual-core machine

[Eli Zaretskii <eliz@gnu.org>]

> Cc: storm@cua.dk (Kim F. Storm),  mindcooler@gmail.com,  emacs-devel@gnu.org
> From: Chris Moore <dooglus@gmail.com>
> Date: Fri, 22 Dec 2006 15:39:40 +0100
> 
> Eli Zaretskii <eliz@gnu.org> writes:
> 
> > There's nothing to prevent a parallel build from compiling 2 Lisp
> > files at the same time, is there?
> 
> Yes, there is, at least on GNU/Linux make isn't used to determine
> which Lisp files to compile.
> 
> During bootstrapping, it's done using the shell:
> 
>   [...] for el in [...] $els; do echo Compiling $el; [...]; done
> 
> and during 'make recompile', it's done using emacs itself:
> 
>   ../src/emacs -batch --no-site-file --multibyte --eval
>   (batch-byte-recompile-directory 0) /home/chris/programs/emacs2/lisp
> 
> Neither of these will honour make's --jobs=2 flag.

It's true that lisp/Makefile.in doesn't give much chance to exploit
parallelism, but it's not true that no parallelism is possible there.
`compile', `recompile', and `cvs-update' have prerequisites that can
be produced in parallel.

leim/Makefile.in is better organized for parallel make, and it's not
inconceivable to have Emacs compile in parallel in lisp/ and in leim/.