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gentian
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 Posted: Sun Apr 01, 2012 5:21 pm Post subject: USE flags for a minimal Openbox System |
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Could someone give me some advice about USE flags appropriate for a really minimal OpenBox system? I don't care about gtk or kde. Not a Gnome/Xfce/Kde fan. My system will be used mainly for java/web development, so I definitely need Eclipse and sun JDK. Any ideas?
thanks! |
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gorkypl
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Location: Kraków, PL
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| Posted: Sun Apr 01, 2012 5:28 pm Post subject: |
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Try these:
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USE="-acl -berkdb -consolekit cups -dbus -gdbm -gnome -gnutls -gstreamer -iconv -java -kde -ldap -libnotify ncurses nls -oss pam -policykit python -qt3 -qt3support -qt4 -perl -samba -sdl smp ssl threads -tk -webkit zlib xmp -zeroconf"
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I have exactly this set on a powerful workstation which I use mainly for scientific research - so no fancy wobbly wondows, just pure work. I use awesome WM, but Openbox shouldn't need anything more. You may want to change "-java" to "java", "cups" to "-cups" if you do not have printer, and according to your CPU you may want to add all or just some of these:
| Code: | | 3dnow 3dnowext mmx mmxext sse sse2 |
This is for global USE flags, rest is fine-tuned in /etc/portage/package.use
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gentian
Tux's lil' helper
Joined: 26 Mar 2012
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| Posted: Sun Apr 01, 2012 5:35 pm Post subject: |
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| gorkypl wrote: | Try these:
| Code: |
USE="-acl -berkdb -consolekit cups -dbus -gdbm -gnome -gnutls -gstreamer -iconv -java -kde -ldap -libnotify ncurses nls -oss pam -policykit python -qt3 -qt3support -qt4 -perl -samba -sdl smp ssl threads -tk -webkit zlib xmp -zeroconf"
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I have exactly this set on a powerful workstation which I use mainly for scientific research - so no fancy wobbly wondows, just pure work. I use awesome WM, but Openbox shouldn't need anything more. You may want to change "-java" to "java", "cups" to "-cups" if you do not have printer, and according to your CPU you may want to add all or just some of these:
| Code: | | 3dnow 3dnowext mmx mmxext sse sse2 |
This is for global USE flags, rest is fine-tuned in /etc/portage/package.use |
Thanks. I don't use 3D at all, apart the xclockmore's 3D animations. |
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gorkypl
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Joined: 04 Oct 2010
Posts: 440
Location: Kraków, PL
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| Posted: Sun Apr 01, 2012 5:40 pm Post subject: |
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3dnow and 3dnowext have nothing in common with 3D acceleration, they are processor-specific USE flags like mmx or sse. They are AMD specific AFAIK.
To see what your processor supports you may do
| Code: | | cat /proc/cpuinfo | grep flags |
Keep in mind that not all CPU flags can be translated into valid USE flags (rather the opposite). I have specified those that I use.
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gentian
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Joined: 26 Mar 2012
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| Posted: Sun Apr 01, 2012 7:12 pm Post subject: |
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| gorkypl wrote: | 3dnow and 3dnowext have nothing in common with 3D acceleration, they are processor-specific USE flags like mmx or sse. They are AMD specific AFAIK.
To see what your processor supports you may do
| Code: | | cat /proc/cpuinfo | grep flags |
Keep in mind that not all CPU flags can be translated into valid USE flags (rather the opposite). I have specified those that I use. |
Just found this wiki. Should I just cp the entries?
http://en.gentoo-wiki.com/wiki/Safe_Cflags/AMD#C-30.2C_C-50.2C_C-60.2C_E-350.2C_E-450_series
| Code: | CHOST="x86_64-pc-linux-gnu"
CFLAGS="-march=amdfam10 -O2 -pipe -mno-3dnow -mcx16 -mpopcnt -mssse3 -msse4a -mmmx"
CXXFLAGS="${CFLAGS}" |
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gorkypl
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Joined: 04 Oct 2010
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Location: Kraków, PL
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| Posted: Sun Apr 01, 2012 7:16 pm Post subject: |
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| gentian wrote: |
Just found this wiki. Should I just cp the entries?
| Code: | CHOST="x86_64-pc-linux-gnu"
CFLAGS="-march=amdfam10 -O2 -pipe -mno-3dnow -mcx16 -mpopcnt -mssse3 -msse4a -mmmx"
CXXFLAGS="${CFLAGS}" |
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No, use -march=native instead, which will auto-detect and fine-tune your processor.
| Code: |
CFLAGS="-march=native -O2 -pipe"
CXXFLAGS="${CFLAGS}"
CHOST="x86_64-pc-linux-gnu"
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gentian
Tux's lil' helper
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| Posted: Sun Apr 01, 2012 7:18 pm Post subject: |
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| gorkypl wrote: | | gentian wrote: |
Just found this wiki. Should I just cp the entries?
| Code: | CHOST="x86_64-pc-linux-gnu"
CFLAGS="-march=amdfam10 -O2 -pipe -mno-3dnow -mcx16 -mpopcnt -mssse3 -msse4a -mmmx"
CXXFLAGS="${CFLAGS}" |
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No, use -march=native instead, which will auto-detect your processor.
| Code: |
CFLAGS="-march=native -O2 -pipe"
CXXFLAGS="${CFLAGS}"
CHOST="x86_64-pc-linux-gnu"
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argh.. I used the -march=k8 during installation since this is an amd cpu.. Did I mess it up really bad? |
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gorkypl
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| Posted: Sun Apr 01, 2012 7:53 pm Post subject: |
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| gentian wrote: |
argh.. I used the -march=k8 during installation since this is an amd cpu.. Did I mess it up really bad? |
No, not at all 
Jut change it now and either rebuild world (emerge -e world) which will take long time, or leave it alone - only the newly built packages will gain optimization, but after half a year you will probably have all your system rebuilt 
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gentian
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Joined: 26 Mar 2012
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| Posted: Mon Apr 02, 2012 6:46 am Post subject: |
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| gorkypl wrote: | | gentian wrote: |
argh.. I used the -march=k8 during installation since this is an amd cpu.. Did I mess it up really bad? |
No, not at all
Jut change it now and either rebuild world (emerge -e world) which will take long time, or leave it alone - only the newly built packages will gain optimization, but after half a year you will probably have all your system rebuilt |
Thanks. Just wondering. Can I use "-march=native" at the beginning of any installation for my boxes? Or do I need to have a working system first? Also, will "-march=native" get all the right flags for me and put them into my make.conf automatically? |
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i92guboj
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| Posted: Mon Apr 02, 2012 8:28 am Post subject: |
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You can use the flag from the beginning.
"-march=native" won't change anything in your make.conf or elsewhere. It'll just instruct gcc to generate binaries that are 100% compatible with your cpu to -hopefully- use 100% of its capabilities. Those binaries won't run in any other machine unless it has a similar enough cpu.
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blackst0ne
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gentian
Tux's lil' helper
Joined: 26 Mar 2012
Posts: 113
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| Posted: Mon Apr 02, 2012 8:49 am Post subject: |
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| i92guboj wrote: | You can use the flag from the beginning.
"-march=native" won't change anything in your make.conf or elsewhere. It'll just instruct gcc to generate binaries that are 100% compatible with your cpu to -hopefully- use 100% of its capabilities. Those binaries won't run in any other machine unless it has a similar enough cpu. |
That "hopefully" statement sounds tad intimidating to me, as I want to have a fast system.. What would the difference be if I use the Cflags mentioned on the cflags reccomendations page for my cpu vs the -march=native?
thx! |
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yngwin
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| Posted: Mon Apr 02, 2012 10:13 am Post subject: |
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That's right. Which is why I recommend to avoid march=native and set cpu specific flags instead.
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gorkypl
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| Posted: Mon Apr 02, 2012 10:35 am Post subject: |
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| gentian wrote: |
That "hopefully" statement sounds tad intimidating to me, as I want to have a fast system.. What would the difference be if I use the Cflags mentioned on the cflags reccomendations page for my cpu vs the -march=native?
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That recommended set of flags my or may not be complete. Using -march=native with a recent gcc version you can be almot sure that ALL gcc flags specific to your CPU are set.
The problem is that such compiled programs may not run on a different CPU (because they were fine-tuned for your CPU, which may or may not be compatible with another one) - thus the problem with distcc.
Also remember that -march=native is a GCC setting and it won't affect USE flags, which you still have to tune manually.
A final note - I remember tests showing that the speed benefit between -march=native and a generic branch like i686 may be very little, and it depends on specific application. So while Gentoo gives you the possibility to use optimized GCC flags, it will not magically turn your HTPC into a SGI workstation.
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gentian
Tux's lil' helper
Joined: 26 Mar 2012
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| Posted: Mon Apr 02, 2012 11:44 am Post subject: |
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| gorkypl wrote: | | gentian wrote: |
That "hopefully" statement sounds tad intimidating to me, as I want to have a fast system.. What would the difference be if I use the Cflags mentioned on the cflags reccomendations page for my cpu vs the -march=native?
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That recommended set of flags my or may not be complete. Using -march=native with a recent gcc version you can be almot sure that ALL gcc flags specific to your CPU are set.
The problem is that such compiled programs may not run on a different CPU (because they were fine-tuned for your CPU, which may or may not be compatible with another one) - thus the problem with distcc.
Also remember that -march=native is a GCC setting and it won't affect USE flags, which you still have to tune manually.
A final note - I remember tests showing that the speed benefit between -march=native and a generic branch like i686 may be very little, and it depends on specific application. So while Gentoo gives you the possibility to use optimized GCC flags, it will not magically turn your HTPC into a SGI workstation. |
Thanks for clarifying. I won't be using distcc, so -march=native should do it for me. |
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BillWho
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| Posted: Mon Apr 02, 2012 12:46 pm Post subject: |
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gentian,
This will show what flags will be used with -march=native
| Code: | | gcc -### -march=native -E /usr/include/stdlib.h 2>&1 | grep "/usr/libexec/gcc/.*cc1" |
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i92guboj
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| Posted: Mon Apr 02, 2012 1:26 pm Post subject: |
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They might work together if all the machines in your network are (and will always be) of the same exact architecture. But I didn't test.
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i92guboj
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| Posted: Mon Apr 02, 2012 1:33 pm Post subject: |
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| gentian wrote: | | i92guboj wrote: | You can use the flag from the beginning.
"-march=native" won't change anything in your make.conf or elsewhere. It'll just instruct gcc to generate binaries that are 100% compatible with your cpu to -hopefully- use 100% of its capabilities. Those binaries won't run in any other machine unless it has a similar enough cpu. |
That "hopefully" statement sounds tad intimidating to me, as I want to have a fast system.. What would the difference be if I use the Cflags mentioned on the cflags reccomendations page for my cpu vs the -march=native?
thx! |
Specially if you use the latest and shinniest CPU and gcc still hasn't specific suport for it you might lose some optimizations. I assure you that it wont hurt at all, and gcc will probably catch up in the next update.
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gentian
Tux's lil' helper
Joined: 26 Mar 2012
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| Posted: Fri Apr 27, 2012 1:05 pm Post subject: |
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| BillWho wrote: | gentian,
This will show what flags will be used with -march=native
| Code: | | gcc -### -march=native -E /usr/include/stdlib.h 2>&1 | grep "/usr/libexec/gcc/.*cc1" |
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This is what I get:
| Code: | | "/usr/libexec/gcc/x86_64-pc-linux-gnu/4.5.3/cc1" "-E" "-quiet" "/usr/include/stdlib.h" "-D_FORTIFY_SOURCE=2" "-march=amdfam10" "-mcx16" "-msahf" "-mpopcnt" "-mabm" "--param" "l1-cache-size=32" "--param" "l1-cache-line-size=64" "--param" "l2-cache-size=512" "-mtune=amdfam10" |
It's a bit daunting for me to understand which are the ones I need to use.. |
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Installing Gentoo
