[vlc-devel] commit: Contribs: Use mtune=pentium2 for Windows (Jean-Baptiste Kempf )

[Jean-Baptiste Kempf]

On Sat, Jan 09, 2010 at 11:14:12AM +0200, Rémi Denis-Courmont wrote :
> Le samedi 9 janvier 2010 01:25:27 git version control, vous avez écrit :
> > vlc | branch: master | Jean-Baptiste Kempf <jb at videolan.org> | Sat Jan  9
> >  00:17:44 2010 +0100| [bcd6f556b7a41613074491553a765e5ed6510e0c] |
> >  committer: Jean-Baptiste Kempf
> > 
> > Contribs: Use mtune=pentium2 for Windows
> 
> That will schedule instructions as if running on a Pentium II, regardless of 
> the actual processor. I guess it is in fact more likely a P3 or P4. I don't 
> know the arcanes of IA-32, but are you sure this is really a good idea?

No, it isn't a good idea.
But well:
 - default on gcc 4.4.2, the windows compiler we will use from now on, is
   mtune=generic, which is i686, which is even lower than pentium2
 - we could try mtune=pentium3, but wouldn't that kill some stupid
   (read: AMD) processors,
 - I believe that we could even --march=pentium2, but that would imply
   --mtune=pentium2.
 - p4 was a bad processors and pentium-m and core* don't follow the same
   architecture, especially with a shorter pipeline.


Maybe mtune=pentium3 could be an option...
I have no strong feeling on that, but I welcome remarks.

Best Regards,

-- 
Jean-Baptiste Kempf
http://www.jbkempf.com/