gentoo on core 2 duo, what CFLAGS?

[neurolepsia]

Hi. I'm going to install gentoo on a core 2 duo intel T5300 @ 1.73Ghz w/ 1 gb ram (notebook)
So, What do you think about my installation, have I to get install amd64 cd or install x86 cd? and, what cflags do you suggest to me for this install?

thanks

P.S. if you need other infos, ask

[hoacker]

what cflags do you suggest to me for this install?

for cflags see: http://gentoo-wiki.com/Safe_Cflags#Inte ... 1xx.2F53xx

[neurolepsia]

Isn't there anythin' that isn't gentoo-wiki? I don't like it and I'm hoping to get some infos from Core 2 duo users ^^

[cyrillic]

have I to get install amd64 cd or install x86 cd?

This part is up to you. It depends if you want to end up with a 64bit system or a 32bit system.

[neurolepsia]

I guess I'll have a 64bit-system. And about CFLAGS? Any suggestions derived from experience (not gentoo-wiki please:P)

[likewhoa]

I guess I'll have a 64bit-system. And about CFLAGS? Any suggestions derived from experience (not gentoo-wiki please:P)

CFLAGS="-O2 -march=nocona -pipe -ftracer -ftree-vectorize"
CHOST="x86_64-pc-linux-gnu"
MAKEOPTS="-j3"

should be good enough until -march=core2 can be used

[neurolepsia]

when -march=core2 will be able? and... another question. During installation, Will have I some problems if I'll use genkernel, or kernel support for 64 is actived by default?

[Ingmarv]

when -march=core2 will be able?

-march=nocona is available from >=sys-devel/gcc-4.3, if i remember correctly

[likewhoa]

when -march=core2 will be able? and... another question. During installation, Will have I some problems if I'll use genkernel, or kernel support for 64 is actived by default?

64bit support will be enabled by default, but you might want to make sure you enabled IA32 Emulation if you're planning on running 32bit apps. when gcc-4.3 becomes stable we will be able to benefit from -march=core2.

[jfp]

Isn't there anythin' that isn't gentoo-wiki? I don't like it and I'm hoping to get some infos from Core 2 duo users ^^

Sometimes the Gentoo-wiki's are great - Sometimes they are not so great. The problem for me has always been in determining which class a specific wiki is in.
I don't see this document mentioned. Perhaps it is worth a read. If memory serves, it seems to me that this doc was just recently (couple of months?) updated.
http://www.gentoo.org/doc/en/gcc-optimization.xml

[Ingmarv]

when -march=core2 will be able?

-march=core2 is available from >=sys-devel/gcc-4.3, if i remember correctly

EDIT: ehr, core2, not nocona ...

[bubbl07]

From http://psykil.livejournal.com/2006/12/03/:

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So, final answer. If you're using GCC 4.1, use -march=prescott for Intel Core Solo/Duo and -march=nocona (and an amd64 profile) for Core 2 Solo/Duo. For GCC 4.2, a Core Solo/Duo should use -march=prescott -mtune=generic, and Core 2 Solo/Duo should be set to -march=nocona -mtune=generic.

gcc-4.3 will add support for the ssse3 instruction set (with the -mssse3 flag, or autoincluded with -march=core2), so this is what I have used, use, and will use:

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gcc-4.1*: "-march=nocona"
gcc-4.2*: "-march=nocona -mtune=generic"
gcc-4.3*: "-march=core2"

I also usually use "-fomit-frame-pointer" (on x86) and "-O2 -pipe" (on x86 and x86_64). It's safe. It works.

[neurolepsia]

only other two questions:

1) Can I compile without problems also if my pc is a notebook? Aren't there any problems such as cpu too much hot and related?

2) If I'll use genkernel I'll get a working system with all REQUIRED supports and modules enabled, won't I ?

thanks a lot

bye

[Elv13]

1)
i had a laptop that compiled svn every night during 3 years and, umm, died, but it was not from overheating, it was just, a bad laptop... But dont worry, cpu will shutdown automatically when it become too hot, it will not break. Laptop CPU are also able to change their clock speed on the fly to cool down.

[bubbl07]

only other two questions:

1) Can I compile without problems also if my pc is a notebook? Aren't there any problems such as cpu too much hot and related?

2) If I'll use genkernel I'll get a working system with all REQUIRED supports and modules enabled, won't I ?

thanks a lot

bye

1) Your computer should shut down automatically if your cpu temperature starts getting too high (although that has yet to happen on my C2D MacBook).

2) Never used genkernel, unfortunately =/.

[michel7]

From http://psykil.livejournal.com/2006/12/03/:

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So, final answer. If you're using GCC 4.1, use -march=prescott for Intel Core Solo/Duo and -march=nocona (and an amd64 profile) for Core 2 Solo/Duo. For GCC 4.2, a Core Solo/Duo should use -march=prescott -mtune=generic, and Core 2 Solo/Duo should be set to -march=nocona -mtune=generic.

gcc-4.3 will add support for the ssse3 instruction set (with the -mssse3 flag, or autoincluded with -march=core2), so this is what I have used, use, and will use:

Code: Select all

gcc-4.1*: "-march=nocona"
gcc-4.2*: "-march=nocona -mtune=generic"
gcc-4.3*: "-march=core2"

I also usually use "-fomit-frame-pointer" (on x86) and "-O2 -pipe" (on x86 and x86_64). It's safe. It works.

Nocona is for 64 bit only! For x86 you still have to use prescott with gcc4.2

[bubbl07]

Nocona is for 64 bit only! For x86 you still have to use prescott with gcc4.2

I mean, I guess so, but the only difference between nocona and prescott is EM64T, and (i686-pc-linux-gnu-)gcc is smart enough to figure out not to compile 64-bit code when compiling 32-bit software even with -march=nocona.

I'm using "-march=nocona" on an EM64T capable P4 on my workstation at work in a gentoo x86 environment and there haven't been any problems in the 11 months I've been using it.

But technically, yes you should use -march=prescott in an x86 environment should you choose to go that route because someone at Intel said so.

As of gcc-4.2, though, running

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ash@ryu ~ $ touch test.c && gcc -v -c test.c -o test -O2 -march=native

to determine what you should be using yields "-march=nocona -mtune=generic" for a Core 2 Duo on x86.

[mxc]

I have been following this thread but can't get my machine to compile 64 bit. I have a machine that was installed with 32 bit. I have donwloaded the amd64 min iso and booted off of that. I then chroot into my current installation and I am attempting to upgrade by doing a emerge -e world.

I have the following in my make.conf

CHOST="x86_64-pc-linux-gnu"
CFLAGS="-march=nocona -O2 -pipe"
CXXFLAGS="${CFLAGS}"

The output from less /proc/cpuinfo says

vendor_id : GenuineIntel
cpu family : 6
model : 15
model name : Intel(R) Core(TM)2 CPU 6300 @ 1.86GHz
stepping : 6

I am using gcc-4.1.2 When I try and compile I get errors like:

"c compiler cannot create executables'
Whats up? How do I upgrade my system?

thanks

[Paapaa]

I think a complete reinstall is the only sane method to upgrade from 32bit to 64bit.

[likewhoa]

I have been following this thread but can't get my machine to compile 64 bit. I have a machine that was installed with 32 bit. I have donwloaded the amd64 min iso and booted off of that. I then chroot into my current installation and I am attempting to upgrade by doing a emerge -e world.

"c compiler cannot create executables'
Whats up? How do I upgrade my system?

thanks

do what Paapaa suggested and that's the only way to go 64bits, you can't compile 64bit code in a 32bit environment, but you can compile 32bit code in a 64bit environment. backup your configuration files and boot from the amd64-livecd and start from scratch.

[meitnerium]

Hello

I'm very confusing with this post, and information I can found on internet about this computer ...

I have a HP pavilion : dv9330ca : http://h10010.www1.hp.com/wwpc/ca/en/ho ... 55953.html

It's a 64 bit computer, and come with Windows Vista 64 bit. I installed gentoo, using this setting in /etc/make.conf :

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CHOST="i686-pc-linux-gnu"
CFLAGS="-march=prescott -O2 -pipe -fomit-frame-pointer"
CXXFLAGS="${CFLAGS}"
ALSA_CARDS="snd-hda-intel"
LIRC_OPTS="--with-driver=mceusb2"
LIRC_DEVICES="mceusb2"
VIDEO_CARDS="nvidia"

So, at the moment, I use the computer in 32 bit ... But the Processor is a pentium one, not the dual core AMD 64. The setting show in http://gentoo-wiki.com/Safe_Cflags is for AMD in 64 bit version, for exemple, for this computer : http://h10010.www1.hp.com/wwpc/ca/en/ho ... 89141.html

My cat /proc/cpuinfo output :

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processor       : 0
vendor_id       : GenuineIntel
cpu family      : 6
model           : 15
model name      : Intel(R) Core(TM)2 CPU         T5500  @ 1.66GHz
stepping        : 6
cpu MHz         : 1667.000
cache size      : 2048 KB
physical id     : 0
siblings        : 2
core id         : 0
cpu cores       : 2
fdiv_bug        : no
hlt_bug         : no
f00f_bug        : no
coma_bug        : no
fpu             : yes
fpu_exception   : yes
cpuid level     : 10
wp              : yes
flags           : fpu vme de pse tsc msr pae mce cx8 apic sep mtrr pge mca cmov pat pse36 clflush dts acpi mmx fxsr sse sse2 ss ht tm pbe nx lm constant_tsc pni monitor ds_cpl est tm2 ssse3 cx16 xtpr lahf_lm
bogomips        : 3330.00
clflush size    : 64

Someone can show me the correct configuration for 64 bit compilation?

[ccastell23]

64bit support will be enabled by default, but you might want to make sure you enabled IA32 Emulation if you're planning on running 32bit apps. when gcc-4.3 becomes stable we will be able to benefit from -march=core2

[neiljw]

Someone can show me the correct configuration for 64 bit compilation?

To achieve a 64 bit environment, you absolutely HAVE to boot from a 64 bit livecd/install cd AND install a 64 bit stage. (OK, it is possible to convert from 32 bits to 64, I've done it, but it's fraught with problems and you really need to know your Gentoo stuff). Once you have that 64 bit stage file installed, everything should be plain sailing for a full 64 bit install.

I have a laptop with exactly the same processor as you and it's happily running 64 bit Gentoo at this very moment.