CPU-specific features...how to find them and/or enable them?

**josolanes** · 10-25-2005

I have a dual AMD Athlon MP 1800+ system and would like to enable any and all cpu-specific features, such as 3DNow. I already have my computer running well as dual-cpu, but would like to enable as many other things as possible (as many programs i run, such as MPlayer, don't believe my cpu's use 3DNow).

I use these USE-flags: "16bit 3dnow 3dnowext S3TC amd ansi applet asm asterisk async bacula-clientonly blender-game browserplugin bzip2 c++ calendar ccache cdrom chroot cpudetection css custom-cflags dar32 dbcp dbus dhcp dio disk-cache double-precision dvd dvdread emoticon fat freetype gimp gimpprint gkrellm glgd glibc glut gzip hal high-ints javascript kqemu math mmxext mp4live mpeg2 mpeg4 mplayer multiprocess network ntfs ogre on-the-fly-crypt pic rdesktop real reiserfs rtc smp sse sse2 subp subtitles svg svgz threads threadsonly toolbar tools transcode usb vcd videos virus-scan win32codecs winbind wma123 wordexp xattr xosd xprint xscreensaver xvid yahoo -cups -kde"

How would I determine if these features are enabled/disabled and how would I go about enabling them? I thought adding them as USE-flags would do it, but I'm not sure if it actually worked.

Thanks in advance for any help

EDIT: i found what MPlayer thinks of my CPU's....here's what it found:

Code:

MPlayer 1.0pre7try2-3.3.6 &#40;C&#41; 2000-2005 MPlayer Team
CPU&#58; Advanced Micro Devices Athlon 4 /Athlon MP/XP Palomino &#40;Family&#58; 6, Stepping
&#58; 2&#41;
Detected cache-line size is 64 bytes
MMX supported but disabled
3DNow supported but disabled
3DNowExt supported but disabled
CPUflags&#58;  MMX&#58; 0 MMX2&#58; 1 3DNow&#58; 0 3DNow2&#58; 0 SSE&#58; 1 SSE2&#58; 0
Compiled with runtime CPU detection - WARNING - this is not optimal!
To get best performance, recompile MPlayer with --disable-runtime-cpudetection.

**josolanes** · 10-26-2005

*bump*
does anyone know how to see what features (such as 3dnow, sse2, mmx, etc) are enabled system-wide?
also, does anyone know of a way to enable mmx, sse2, 3dnow, etc system-wide? i'm sure there's a way to do this...

i'd like to know as, i'd assume, these should make a difference enabled vs disabled.

don't mind the mplayer example (if it's just specific to that program), i'll sort it out on my own.

**scientica** · 10-26-2005

does anyone know how to see what features (such as 3dnow, sse2, mmx, etc) are enabled system-wide?
also, does anyone know of a way to enable mmx, sse2, 3dnow, etc system-wide? i'm sure there's a way to do this...

for gentoo, USE flags. "emerge --info" will show the USE flags "inaction", some might be masked by the profile (eg mmx is masked (-mmx) for AMD64's to void the risc of x86 asm in x86-64 code).

check out /proc/cpuinfo for the list of things supported by your CPU and linux.
HTH

**jaboua** · 10-28-2005

You can also use it in the CFLAGS, for example CFLAGS="-O2 -pipe -m3dnow -mmmx"

See the official docs for gcc for more info.

**josolanes** · 10-29-2005

oh, ok..thanks for the help guys. so, when i compile something, it's set into the program all the specs of the processor based on the use-flags and the cflags?

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