[CentOS] latest kernel - version question

Mon Jan 10 20:35:22 UTC 2011
Robert Heller <heller at deepsoft.com>

At Mon, 10 Jan 2011 18:25:22 +0100 CentOS mailing list <centos at centos.org> wrote:

> 
> El 09/01/2011 16:31, Robert Heller escribió:
> 
> > The kernel itself is optimized for the i686 processor.  It is possible
> > to custom build a kernel for the i586, i486, or i386 if you really have
> > a processor that old.
> 
> What is the sense of optimize a kernel for i686 and then distribute most 
> of packages for i386?

Most packages don't actualy do anything where process-specific
optimizations would make any noticable differences.  Note: glibc itself
is optimized for i686 and since just about all programs use glibc, they
would all get this advantage.

Optimizing the kernel not only relates to generic speed, etc.
advantages but also a pile of kernel-level 'features' the newer
procossors provide (stuff involving process scheduling, virtual memory
management, and I/O / DMA addressing / processing).  These various 
kernel-level 'features' are not accessable by user-mode processes, so
adding in those features / instructions is not meaningful for user-mode
code (most packages).

> 
> For example in CentOS-5:
> 
> kernel-2.6.18-194.el5.i686.rpm
> php-5.1.6-27.el5.i386.rpm
> httpd-2.2.3-43.el5.centos.i386.rpm
> mysql-server-5.0.77-4.el5_4.2.i386.rpm
> 
> Regards,
> 
> --
> Santi Saez
> http://woop.es
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> 
>                        

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Robert Heller             -- 978-544-6933 / heller at deepsoft.com
Deepwoods Software        -- http://www.deepsoft.com/
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