[Mplayer-users] gcc 2.95.2 vs. 3.0

Arpi arpi at thot.banki.hu
Sun Jun 24 04:31:56 CEST 2001


Just compiled and try gcc 3.0 stable.
And the results is very big surprise! It makes *SLOWER* code!

test file:  (opendivx with postprocessing, this stuff is written in C)
# mplayer -osdlevel 0 -nosound -benchmark 1800.avi -vo null -pp 15
VIDEO:  [divx]  640x352  24bpp  23.98 fps  1865.1 kbps (227.7 kbyte/s)

hardware: celeron-2 600 @ 900MHz (100MHz FSB), 256MB RAM (PC133, at 2/2/2)
(sse,mmx,mmxext enabled)

gcc 2.95.2 result:  (flags: -O4 -march=i686 -mcpu=i686 -pipe -ffast-math)
BENCHMARKs: V:   5.087s VO:   0.001s A:   0.000s Sys:   0.013s =    5.101s
BENCHMARK%: V: 99.7160% VO:  0.0258% A:  0.0000% Sys:  0.2582% = 100.0000%

gcc 3.0 result:  (flags: -O4 -march=i686 -mcpu=i686 -pipe -ffast-math)
BENCHMARKs: V:   5.194s VO:   0.001s A:   0.000s Sys:   0.013s =    5.208s
BENCHMARK%: V: 99.7309% VO:  0.0221% A:  0.0000% Sys:  0.2471% = 100.0000%

yes, speed diff isn't big, but i was prepared for big speed boost by 3.0,
and then i got speed loss! :(

if i recompile C-only parts of decore with intel's commercial C compiler
(free beta available for linux), it's about 15% faster:

icc result:  (optim. flags: -O2 -fp -rcd -tpp6 -xiMK)
BENCHMARKs: V:   4.415s VO:   0.001s A:   0.000s Sys:   0.013s =    4.429s
BENCHMARK%: V: 99.6676% VO:  0.0290% A:  0.0000% Sys:  0.3034% = 100.0000%

A'rpi / Astral & ESP-team

mailto:arpi at thot.banki.hu

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