[mythtv] New configure script oddities
Blammo
blammo.doh at gmail.com
Wed Mar 23 20:38:44 UTC 2005
> I'm using the flags recommended in the 0.17 docs, I believe that
> testing showed that optimizing for the Athlon XP was slower than
> optimizing for the pentiumpro with mmx enabled (i.e. pentium2).
I''ll have to go look at the doc. Here's the compile optimizations I'm
testing on a commflag box, specific to the Barton chip I'm running in
most of my machines:
-march=athlon-xp -mfpmath=sse -msse -mmmx -m3dnow
I'm not having any trouble with the single machine I'm testing it on,
and it does appear to make quite an increase in commflag performance.
I'll post some numbers once I get a chance to test some more. On the
bright side it didn't die during compile. :)
The options above were generated from a script I found called
"gccopts", which checks /proc/cpuinfo and makes guesses based on that.
I'll attach it to the end of this email, in case any one else wants to
play with it. (Since I'm sure the CR/LF's may get munged, I'll email
it to anyone who wants)
---------------------------------------------------
#!/bin/sh
# Author: pixelbeat
#This script is Linux specific
#It should work on any gcc >= 2.95 at least
#these apply to any arch (just here for reference)
unsafe_math_opts="-ffast-math -fno-math-errno
-funsafe-math-optimizations -fno-trapping-math"
gcc_version=`gcc -dumpversion | sed
's/\([0-9]\{1,\}\.[0-9]\{1,\}\)\.*\([0-9]\{1,\}\)\{0,1\}/\1\2/'`
IFS=":"
while read name value; do
unset IFS
name=`echo $name`
value=`echo $value`
IFS=":"
if [ "$name" == "vendor_id" ]; then
vendor_id="$value"
elif [ "$name" == "cpu family" ]; then
cpu_family="$value"
elif [ "$name" == "model" ]; then
cpu_model="$value"
elif [ "$name" == "flags" ]; then
flags="$value"
fi
done < /proc/cpuinfo
unset IFS
if [ "$vendor_id" == "AuthenticAMD" ]; then
if [ "$cpu_family" == "4" ]; then
_CFLAGS="$_CFLAGS -march=i486"
elif [ "$cpu_family" == "5" ]; then
if [ "$cpu_model" -lt "4" ]; then
_CFLAGS="$_CFLAGS -march=pentium"
elif [ "$cpu_model" == "6" ] || [ "$cpu_model" == "7" ]; then
_CFLAGS="$_CFLAGS -march=k6"
elif [ "$cpu_model" == "8" ] || [ "$cpu_model" == "12" ]; then
if expr $gcc_version '>=' 3.1 >/dev/null; then
_CFLAGS="$_CFLAGS -march=k6-2"
else
_CFLAGS="$_CFLAGS -march=k6"
fi
elif [ "$cpu_model" == "9" ] || [ "$cpu_model" == "13" ]; then
if expr $gcc_version '>=' 3.1 >/dev/null; then
_CFLAGS="$_CFLAGS -march=k6-3"
else
_CFLAGS="$_CFLAGS -march=k6"
fi
fi
elif [ "$cpu_family" == "6" ]; then
if [ "$cpu_model" -le "3" ]; then
if expr $gcc_version '>=' 3.0 >/dev/null; then
_CFLAGS="$_CFLAGS -march=athlon"
else
_CFLAGS="$_CFLAGS -march=k6"
fi
elif [ "$cpu_model" == "4" ]; then
if expr $gcc_version '>=' 3.1 >/dev/null; then
_CFLAGS="$_CFLAGS -march=athlon-tbird"
elif expr $gcc_version '>=' 3.0 >/dev/null; then
_CFLAGS="$_CFLAGS -march=athlon"
else
_CFLAGS="$_CFLAGS -march=k6"
fi
elif [ "$cpu_model" -ge "6" ]; then #athlon-{4,xp,mp}
if expr $gcc_version '>=' 3.1 >/dev/null; then
_CFLAGS="$_CFLAGS -march=athlon-xp"
elif expr $gcc_version '>=' 3.0 >/dev/null; then
_CFLAGS="$_CFLAGS -march=athlon"
else
_CFLAGS="$_CFLAGS -march=k6"
fi
fi
fi
else #everything else "GenuineIntel"
if [ "$cpu_family" == "3" ]; then
_CFLAGS="$_CFLAGS -march=i386"
elif [ "$cpu_family" == "4" ]; then
_CFLAGS="$_CFLAGS -march=i486"
elif [ "$cpu_family" == "5" ] && expr $gcc_version '<' 3.1 >/dev/null; then
_CFLAGS="$_CFLAGS -march=pentium"
elif [ "$cpu_family" -ge "6" ] && expr $gcc_version '<' 3.1 >/dev/null; then
_CFLAGS="$_CFLAGS -march=pentiumpro"
elif [ "$cpu_family" == "5" ]; then
if [ "$cpu_model" != "4" ]; then
_CFLAGS="$_CFLAGS -march=pentium"
else
_CFLAGS="$_CFLAGS -march=pentium-mmx" #No overlap with other vendors
fi
elif [ "$cpu_family" == "6" ]; then
if echo "$flags" | grep -vq cmov; then #gcc incorrectly
assumes i686 always has cmov
_CFLAGS="$_CFLAGS -march=pentium -mcpu=pentiumpro" #VIA
CPUs exhibit this
else
if [ "$cpu_model" == "0" ] || [ "$cpu_model" == "1" ]; then
_CFLAGS="$_CFLAGS -march=pentiumpro"
elif [ "$cpu_model" -ge "3" ] && [ "$cpu_model" -le "6" ];
then #4=TM5600 at least
_CFLAGS="$_CFLAGS -march=pentium2"
elif [ "$cpu_model" -ge "7" ] && [ "$cpu_model" -le "11"
]; then #9 invalid
_CFLAGS="$_CFLAGS -march=pentium3"
fi
fi
elif [ "$cpu_family" == "15" ]; then
_CFLAGS="$_CFLAGS -march=pentium4"
fi
fi
if expr $gcc_version '>=' 3.1 >/dev/null; then
if echo "$flags" | grep -q sse2; then
_CFLAGS="$_CFLAGS -mfpmath=sse -msse2"
elif echo "$flags" | grep -q sse; then
_CFLAGS="$_CFLAGS -mfpmath=sse -msse"
fi
if echo "$flags" | grep -q mmx; then
_CFLAGS="$_CFLAGS -mmmx"
fi
if echo "$flags" | grep -q 3dnow; then
_CFLAGS="$_CFLAGS -m3dnow"
fi
fi
echo "$_CFLAGS"
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