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Re: subarchitectures (was Re: What to do with optimization flags ? )

On Thu, Dec 07, 2000 at 12:14:53PM -0500, Camm Maguire wrote:
> Greetings, and thank you so much for this helpful information!  
> 1) I notice you reference 'apic'.  Do you happen to know to what that
>    refers?  The ones I recognize are mmx,xmm,and amd3d.
> 2) There are some small differences between k6 amd3d and athlon amd3d.
>    Do you know which is referred to here?

The flags correspond to output from /proc/cpuinfo (the "flags" field).
Like on my Celeron laptop I have:

%cat /proc/cpuinfo | grep flags
flags           : fpu vme de pse tsc msr pae mce cx8 sep mtrr pge mca cmov pat pse36 pn mmx fxsr

> 3) We've already had a brief discussion about this, but to fill you
>    in, the major two alternatives are to either have several package
>    binaries for each sub-arch, or to have all libs in one binary
>    package.  In either case, it sounds like a good ide to use the
>    right subdir.  I was wondering if you had a suggestion between
>    these two alternatives.

For libc6 I use seperate packages, but that is mainly because I don't want
to force everyone to install all of these libs (since everyone has to have
libc6 whether they want it or not :)

The downside to seperate packages, is the increase in the Packages file,
and the number of available packages in the dist.

> 4) Most importantly, it appears that atlas cannot cross-compile,
>    i.e. the compiled code must *run* on the compilation machine.  From
>    what I can see, this makes it impossible to autobuild fully
>    optimized version(s) of this package given the current machines at
>    Debian's disposal.  I can set the package up to autobuild a generic
>    x86 lib, like it does currently, which will autobuild successfully.
>    But I could also produce a fully optimized binary package covering
>    p3,p2,k6,k7 given the machines available here.  My question: is
>    there anyway to get such a binary package to override the
>    auto-built binary packages in the distribution?

That's a downfall in atlas, IMO. There should be a way to compile for a
CPU, without actually having that CPU. You will most likely have to hack
the atlas build process to get this done.

/  Ben Collins  --  ...on that fantastic voyage...  --  Debian GNU/Linux   \
`  bcollins@debian.org  --  bcollins@openldap.org  --  bcollins@linux.com  '

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