[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
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