[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

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

-- Daniel

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