CentOS docs - Jan 2010 - Article on building i586 CentOS-5 kernel

Dear all,

I was searching for a recent i586 for CentOS-5 in the CentOSPlus 
repository.  Finding none, I decided to try my hands at building one.  I 
have documented the changes made to the stock SRPM for building an i586 
kernel on a temporary wiki page:

    * http://wiki.centos.org/TimothyLee/centos5_i586_patch

These instructions have been successfully tested against the 
2.6.18-164.10.1.el5 kernel.  All comments are welcomed.

I have two questions for the development team:

    * Is this article suitable for publication on the wiki?
    * Can the changes mentioned in that article be incorporated into the
      stock SRPM?  (As far as I know, non-i586 builds should not be
      affected)

Regards,
Timothy Lee

Timothy Lee wrote:
>   Dear all,
> 
> I was searching for a recent i586 for CentOS-5 in the CentOSPlus 
> repository.  Finding none, I decided to try my hands at building one.  I 
> have documented the changes made to the stock SRPM for building an i586 
> kernel on a temporary wiki page:
Wow. There are Pentium machines still running out there?

You do know that Pentium optimizations are only for Pentiums and that 
such binaries could actually run slower on anything Pentium-II/Pentium 
Pro and above than i386 (actually i486 optimized binaries iirc - must 
check gcc) optimized binaries due to the architecture differences of the 
Pentium?

Been such a long time since i saw any mention of i586.

Hi,

I am lagging a bit on the -docs maillist backlog, will try and catchup 
over the next few days.

On 01/11/2010 06:17 AM, Timothy Lee wrote:
>      * http://wiki.centos.org/TimothyLee/centos5_i586_patch
>
> These instructions have been successfully tested against the
> 2.6.18-164.10.1.el5 kernel.  All comments are welcomed.
sounds good :)
> I have two questions for the development team:
>
>      * Is this article suitable for publication on the wiki?
I'd say no, not here in the user facing wiki
>      * Can the changes mentioned in that article be incorporated into the
>        stock SRPM?  (As far as I know, non-i586 builds should not be
>        affected)
No, but there is a big open door in the c5plus kernel window. That would 
be the best place for this.


However, expanding a bit ( and this conversation might be better for 
-devel rather than -docs ).

Is the modified kernel the the only bit of change you need for i586 
support ? I'd think a glibc.i586 might be worth doing as well. And there 
were a few other packages that were required to be patched on c4 to make 
it work for i586. How many of those are needed here as well ?  And there 
are a lot of patches in the kernel tree that might not impact the i586 
code at all. eg. whats the state of xen in this i586 kernel ?

If there is reasonable interest in running a i586 tree, then imho, a SIG 
dedicated to this would be the best route to go. It would also make it 
possible to have a i586 specific tree that can be maintained in parallel 
to the main core distro.

-- 
Karanbir Singh
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