[MPlayer-users] Just wondering

[Reimar Döffinger]

Hello,
On Wed, Sep 27, 2006 at 11:59:58AM +0200, Guillaume POIRIER wrote:
> On 9/27/06, Alexander Strop <strop at erlm.siemens.de> wrote:
> >Yesterday i tested the performance from mencoder on two different
> >plattforms. I compiled 1.0pre7try2 on a Itanium 1.6 with Debian 3.1 and
> >on a Pentium4 Xeon 2.5 Ghz (HP Compaq DL380).
> >Then i encoded a Mpg2 file to Mpeg4 with mp3 sound. This file is about 4MB.
> >Encoding on the Itanium Machine: 1min. 15sec.
> >Encoding on the DL380: 45 sec.
> 
> Mainly because x264 is ultra-optimized for x86 CPUs though
> hand-written ASM, and Itanium port doesn't have any.

That, and the fact that the Itanium is basically a cache on feet without
any intelligence of its own. You can't expect to get good performance
out of it except for pure number-crunching tasks involving a lot of
floating-point operations. For HD-resolution stuff the Itanium's giant cache
might give it a bit of advantage though (though only if it's an Itanium
2, the original Itanium only had so much cache because otherwise the
performance would have been below that of other CPUs in all cases).
In addition since it has no intelligence of it's own and gcc doesn't
have too much of it either, using Intel's C-Compiler is a must.
Unfortunately icc probably won't produce working code for some parts of
MPlayer, e.g. libmpeg2 (based on experience on x86).

Greetings,
Reimar Döffinger