Am Montag, 12. März 2012, 12:32:01 schrieb Alex Schuster: > Hi there! > > Recently, my sister could not log in to KDE after I had done some > updates. X crashed when loggin into KDE. It turned out that > x11-libs/qt-gui-4.7.4-r1 was the problem when compiled with explict > CFLAGS, instead of just using -march=native. > > Her CPU is an AMD A6-3500 with three cores. As I have a PC that is a > little faster, I thought I'd use my four cores in addition via distcc. My > CPU is different, so using -march=native would be bad. I visited [*], and > used this command to find out what -march=native does: > > leela # cc -march=native -E -v - </dev/null 2>&1 | grep cc1 > /usr/libexec/gcc/x86_64-pc-linux-gnu/4.5.3/cc1 -E -quiet -v - > -D_FORTIFY_SOURCE=2 -march=amdfam10 -mcx16 -msahf -mpopcnt -mabm --param > l1-cache-size=64 --param l1-cache-line-size=64 --param > l2-cache-size=1024 -mtune=amdfam10 > > So I defined these CFLAGS: > CFLAGS="-pipe -march=amdfam10 -O2 -mcx16 -msahf -mpopcnt -mabm \ > --param l1-cache-size=64 --param l1-cache-line-size=64 \ > --param l2-cache-size=1024" > > The command above does not tell about SSE stuff, so I used this one to > find out about that: > > leela # echo | gcc -dME - -march=native | grep -Ei 'SSE|3DNOW|MMX' | sort > #define __3dNOW_A__ 1 > #define __3dNOW__ 1 > #define __MMX__ 1 > #define __SSE2_MATH__ 1 > #define __SSE2__ 1 > #define __SSE3__ 1 > #define __SSE4A__ 1 > #define __SSE_MATH__ 1 > #define __SSE__ 1 > > And I added "-msse -msse2 -msse3 -msse4 -m3dnow -mmmx" to CFLAGS. > > Anything wrong with that? Because when I compile > x11-libs/qt-gui-4.7.4-r1, using distcc with local and remote clients, > X will crash when logging into KDE. gcc is at version 4.5.3 on both PCs. > Distcc worked fine in the past, but those were other clients. > > Wonko > > [*] http://en.gentoo-wiki.com/wiki/Safe_Cflags#-march.3Dnative
and of course we all just use our crystal balls because it is so easy without the error message. -- #163933
