reducing compiler instances during buildkernel

[Joerg Sonnenberger]

On Mon, Nov 07, 2011 at 06:46:24PM +1100, Peter Jeremy wrote:
> On 2011-Nov-05 22:30:21 +0000, Alexander Best <arundel at freebsd.org> wrote:
> >wouldn't it be possible to somehow spawn N gcc or clang instances
> >(make -jN buildkernel) and then pipe the src to one of those N instances?
> >just like with something like multics N processes were started and then people
> >used the job control language to load binaries into those processes.
> 
> This is likely to require very non-trivial changes to gcc or clang.
> The major issue is that the process needs to be in a known initial
> state before beginning a compile - and it's very unlikely that the
> compiler cleans itself up enough to return to that state.

Actually, the real problem is that a full cleanup is likely to be as
expensive as fork+exec.

Joerg