Re: A Radical Multi-Arch Counter-Proposal

[Goswin von Brederlow <brederlo@informatik.uni-tuebingen.de>]

Xavier Roche <rocheml@httrack.com> writes:

> Hi,
> 
> On Thu, Jan 15, 2004 at 11:36:45PM -0500, Anthony DeRobertis wrote:
> >      A. dpkg will be extended to support installing two packages with
> >         the same name, but different ABIs, as previously proposed.
> >      B. dpkg will be extended to support two packages with the same name
> >         (as above) both owning the same file. It will only remove a file
> >         from the filesystem when the last owning package is removed.
> 
> This is not to throw another (slightly off-topic on devel-x86-64)
> though, but I was (stupidely) wondering if the 32/64 packaging
> questions and migration could not also be extended to a possibly
> "586 optimized" packages asked by many folks (supposely 5% to 30%
> performances increase) ; see related information at
> http://debian-i586.sourceforge.net/

That already works in dpkg multiarch. But i386 - i686 provide ABI:
ia32. All those packages will be compatible but conflict. You can
install an optimized libfoo:i686 and a foo:i386 binary that uses
it. Since they conflict there is no change needed to dpkg there like
for amd64.

> I know this has been discussed before (the 586 optimized packages),
> and I don't want to fire another-yet-potential flame, but
> considering an "x86-x586" arch is potentially similar to "x86-64"
> (different /lib place, potentially same package names, possibility
> to install different flavours ..)

There is also a mechanism in ld to choose optimized libs depending on
the cpu capabilities (like MMX or SSE) that already is at work for
glibc and ssl. I think its even in woody.

> If the dpkg system has to be improved for x86-64, it might be a good
> idea to allow such thing ?
> 
> Just a slightly off-topic idea.
> [Sorry for the potentially bad english]

MfG
        Goswin