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On 03/12/2012 12:32:01 PM, Alex Schuster wrote: |
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> Hi there! |
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> |
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> Recently, my sister could not log in to KDE after I had done some |
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> updates. X crashed when loggin into KDE. It turned out that |
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> x11-libs/qt-gui-4.7.4-r1 was the problem when compiled with explict |
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> CFLAGS, instead of just using -march=native. |
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> |
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> Her CPU is an AMD A6-3500 with three cores. As I have a PC that is a |
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> little faster, I thought I'd use my four cores in addition via |
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> distcc. My |
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> CPU is different, so using -march=native would be bad. I visited [*], |
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> and |
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> used this command to find out what -march=native does: |
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> |
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> leela # cc -march=native -E -v - </dev/null 2>&1 | grep cc1 |
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> /usr/libexec/gcc/x86_64-pc-linux-gnu/4.5.3/cc1 -E -quiet -v - |
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> -D_FORTIFY_SOURCE=2 -march=amdfam10 -mcx16 -msahf -mpopcnt -mabm |
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> --param |
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> l1-cache-size=64 --param l1-cache-line-size=64 --param |
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> l2-cache-size=1024 -mtune=amdfam10 |
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> |
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> So I defined these CFLAGS: |
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> CFLAGS="-pipe -march=amdfam10 -O2 -mcx16 -msahf -mpopcnt -mabm \ |
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> --param l1-cache-size=64 --param l1-cache-line-size=64 \ |
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> --param l2-cache-size=1024" |
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> |
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> The command above does not tell about SSE stuff, so I used this one to |
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> find out about that: |
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> |
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> leela # echo | gcc -dME - -march=native | grep -Ei 'SSE|3DNOW|MMX' | |
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> sort |
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> #define __3dNOW_A__ 1 |
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> #define __3dNOW__ 1 |
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> #define __MMX__ 1 |
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> #define __SSE2_MATH__ 1 |
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> #define __SSE2__ 1 |
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> #define __SSE3__ 1 |
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> #define __SSE4A__ 1 |
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> #define __SSE_MATH__ 1 |
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> #define __SSE__ 1 |
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> |
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> And I added "-msse -msse2 -msse3 -msse4 -m3dnow -mmmx" to CFLAGS. |
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> |
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> Anything wrong with that? Because when I compile |
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> x11-libs/qt-gui-4.7.4-r1, using distcc with local and remote clients, |
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> X will crash when logging into KDE. gcc is at version 4.5.3 on both |
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> PCs. |
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> Distcc worked fine in the past, but those were other clients. |
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> |
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> Wonko |
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> |
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> [*] http://en.gentoo-wiki.com/wiki/Safe_Cflags#-march.3Dnative |
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> |
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|
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I normally check the flags entry in cat /proc/cpuinfo to decide |
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what's supported on a given CPU. |
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|
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Helmut. |
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