[MPlayer-users] configure --disable-network fails on make

Krzysztof Duchnowski amidk75 at gmail.com
Fri Mar 14 23:12:12 CET 2008


Alexander Bokovikov pisze:

> Krzysztof Duchnowski wrote:

>> "--disable-runtime-cpudetection" ???

> I'm not sure I'm understanding what is it. In fact, what I need is just to
> get MEncoder, compiled with the runtime CPU detection. because compiled on
> my notebook would not work on older CPU's. At least earlier I already got
> this effect.

No. You don't need runtime CPU detection  - it's somehow broken and in
result compiled code is much slower thatn bare i386 code.
You need to compile it to i386 code, thus you need flag
"--target=i386-linux":

CFLAGS=i386 ./configure --enable-largefiles --disable-runtime-cpudetection
--target=i386-linux

> I beleaved that cpu detection is made at compiletime by default. In my log
> file I see appropriate lines concerning CPU detected. On the other hand I
> see an explicit message when I use "--enable-runtime-cpudetection".
> Therefore I thought that "--disable-runtime-cpudetection" just does no
> matter. Am I wrong?

Yes. CPU detection is made during each mplayer/mencoder run with special
CPU detection code compiled with this "--enable-runtime-cpudetection"
flag and after that some parts of code is replaced with special compiled
routine but... as I understand, this detection is made every time that
routine began to be used so if something is used in a loop then this
runtime CPU detection is run also in a loop with it and in every loop it
detects CPU and changes routine to compiled to your CPU wich causes
massive slowdown as the result.

-- 
Krzysztof 'DK75' Duchnowski
GetFirefox - http://www.mozilla.com/firefox/
Konfiguracja UTF-8 dla czytników - http://evil.pl/pip/utf/





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