[Debian-ppc64-devel] Status of debian ppc64?

[Benjamin Herrenschmidt]

On Tue, 2005-03-08 at 13:39 +0100, Sven Luther wrote:
> On Tue, Mar 08, 2005 at 01:45:41PM +0100, Andreas Jochens wrote:
> > On 05-Mar-08 13:08, Sven Luther wrote:
> > > No, i believe you are wrong, or partially so at least. I mean, it may have
> > > changed in the last few month, but last this was discussed, both redhat and
> > > suse where taking the biarch approach, while gentoo goes the pure-64bit
> > > approach.
> > 
> > What exactly do you mean by 'biarch approach' vs. 'pure-64bit approach'?
> > I guess that the term 'pure-64bit approach' comes from the amd64 case.
> > The Debian amd64 'pure64' port started with a setup and toolchain which 
> > was not able to produce 32 binaries. But this is history. 
> > Since a long time the Debian amd64 port has a 'biarch' toolchain 
> > which can produce 32 bit binaries and 32 bit binaries and libraries 
> > run without problems on the amd64 'pure64' port. 
> > 
> > The ppc64 port on alioth also uses a biarch setup and toolchain. 
> > 32-bit binaries and libraries will run fine.
> 
> I think the difference is in what you run per default, 32bit vs 64bit, and if
> you have powerpc or ppc64 as arch in the packages.
> 
> Notice that the ppc64 port on alioth is not an official port too.

Note that you also want a biarch compiler anyway. The kernel pretty much
requires one lately (at least will with current bk).

> > > > The Debian ppc64 port on alioth is quite similar to the ppc64 ports of
> > > > the other major distributions. One minor difference between RedHat/Suse 
> > > > on one side and Debian/Gentoo on the other is that RedHat and Suse 
> > > > put native 64-bit libraries in '/lib64' and 32-bit libraries in '/lib', 
> > > > while Debian and Gentoo put native 64-bit libraries in '/lib' and
> > > > 32-bit libraries in '/lib32'.
> > > 
> > > Exactly what i was saying, the only difference is the extent of the 64bit
> > > rebuilds. 
> > > 
> > > But then, again the IBM ppc64 folk tell me that there is a slight performance
> > > hit in running 64bit userland if it is not necessary, and i wonder what you
> > > reply to this ? 
> > 
> > It is too early to confirm or reject this. I only made some very 
> > non-scientific tests with the standard tools and with compilations.
> > In these prelimiary test, I could not detect any significant differences.
> > Do you have any detailed numbers or specific tests that I could run to
> > verify this?
> 
> Nope, but since it comes from the guys who work at IBM ozlabs doing ppc64
> port, i am ported to believe them.

Just do a kernel compile benchmark :)

Ben.