[mythtv-users] configure did not detect my cpu

Daniel Kristjansson danielk at cuymedia.net
Thu Jan 11 23:21:59 UTC 2007


On Thu, 2007-01-11 at 16:07 -0700, John P Poet wrote:
> 
> On 1/11/07, Daniel Kristjansson <danielk at cuymedia.net> wrote:
>         On Wed, 2007-01-10 at 18:45 -0800, mikal at stillhq.com wrote:
>         > Just doing what I am told (a search implies no one else has
>         sent this in
>         > yet)...
>         This CPU is in SVN head.. 
>         
>         -- Daniel
>
> Hi Daniel,
> 
> I assume you have seen this:
> 
> http://psykil.livejournal.com/2006/12/03/
> 
> I don't have a core cpu, but would love to get one... 

No I hadn't seen that. It might be worth it to add a gcc 4.2
check just for the "-march=native". We actually limit the
CPU's we optimize for to avoid compiler bugs mucking up trac.

I did some timing studies before adding "--enable-proc-opt"
and with MythTV the only thing that sped things up
significantly was compiling for a cmov capable processor,
i.e. PentiumPro or later.

Compiling for the P4 gave and extra 10% so we do that too.
Finally, "-mfpmath=sse" added another 10% speedup, but it
didn't caused problems so it's not used when you use
"--enable-proc-opt".

We don't compile specifically for any Athlon processor
unless the architecture demands it because those flags
actually slow down the executable..

-- Daniel




More information about the mythtv-users mailing list