Gentoo Forums
Gentoo Forums
Gentoo Forums
Quick Search: in
Need to know a few things before I install Gentoo.
View unanswered posts
View posts from last 24 hours

 
Reply to topic    Gentoo Forums Forum Index Gentoo on AMD64
View previous topic :: View next topic  
Author Message
jchahn
n00b
n00b


Joined: 16 Jan 2004
Posts: 19

PostPosted: Mon Jul 31, 2006 4:40 pm    Post subject: Need to know a few things before I install Gentoo. Reply with quote

I have been using linux for about 5 years now. I haven't had a linux distro on my machine in almost a year because I have a sound blaster x-fi soundcard, which won't have any linux drivers until 2nd quarter of 2007 (according to creative). I couldn't stand windows any longer so I threw my old audigy card back in and am about to put Gentoo back on. I just need a few questions answered. I'm sure the answers are already here somewhere, I just don't know where to look or what it would be listed under exactly.

Now that the stage1 and stage2 installs are no longer supported, I figure I'll just follow the handbook and do a stage3. I have heard people mention in passing on here that you can do something that will basically make a stage3 have the same level of optimization as a stage1. Is there documentation somewhere that explains just exactly how to achieve that? As far as I can tell, it has something to do with emerging the latest version of GCC (using particular USE flags), then doing an emerge world, which will recompile everything of importance with the new optimizations. I just need a link that explains exactly how to do it so I don't miss a step.

Also, as long as I don't get the no-multilib version, I should have support for 32bit emulation by default, right?

I know that there is a USE flag called emul_x86_32 or something like that.. do I need to use that to get 32bit emulation or does it do it by default now?

Thanks in advance for the help everyone, :) .
John
Back to top
View user's profile Send private message
garlik42
n00b
n00b


Joined: 17 Dec 2002
Posts: 57
Location: Connecticut USA by the water ...

PostPosted: Mon Jul 31, 2006 5:20 pm    Post subject: Reply with quote

Stage 1/2 not supported ?? I didn't get the memo ... :D
Just looked in a couple of manuals, and by gosh your right ...
I hope the scripts are still there for us die hards ...

To update the entire system (IE the stage3 optimization you mention)

This command will rebuild everything, make sure you tweak whatever settings you wish in make.conf before.
emerge -u world --deep --emptytree

You will most likely end up with a etc-update situation after doing this, so make sure you don't flummox your /etc/fstab and other important configs.
Back to top
View user's profile Send private message
downey
Tux's lil' helper
Tux's lil' helper


Joined: 17 Nov 2004
Posts: 107
Location: Calgary, Canada

PostPosted: Mon Jul 31, 2006 5:37 pm    Post subject: Reply with quote

I believe that the way you get a fully optimized system is by doing the stage 3 install up to the system build and then changing the CFLAGS and CHOST variables to reflect what system you have. I think the default AMD64 stage3 build is pretty good, but it has been a while since I did it. Here is my CFLAGS and CHOST:
Code:
CFLAGS="-march=k8 -O2 -pipe"
CHOST="x86_64-pc-linux-gnu"

I don't think it is much different than the default but I haven't checked in a while. Some people use -O3 but I can't say there is much difference and -O2 is more stable. After you make the changes to the make.conf you MUST recompile system again. This sets up your build system using the new CFLAGS and CHOST. Then you can continue with the rest of the install. If you look at the install doc I believe this is all explained in better detail.
http://www.gentoo.org/doc/en/gentoo-x86-quickinstall.xml Look in the "Last configuration touches" section. It looks like the install is a lot different than when I did it so it would be best to read the handbook all the way through.

I believe multilib is on by default, I don't have it in my USE flags. You can turn it off and it will speed up some of your install as you won't need to build the 32 bit version of some libraries, but for the most part you want to have it. You will be able to run 32 bit apps by default. Really there isn't any emulation done but it does depend on what you define as emulation.
Back to top
View user's profile Send private message
jchahn
n00b
n00b


Joined: 16 Jan 2004
Posts: 19

PostPosted: Mon Jul 31, 2006 7:57 pm    Post subject: Reply with quote

Thanks for the replies everyone.

downey wrote:
Really there isn't any emulation done but it does depend on what you define as emulation.


So when running in a 64 bit environment, the amd chips actually run 32 bit apps natively? I was under the impression that if you ran a system in 64 bit, and ran a 32 bit app on it, it was emulating 32 bit mode...
Back to top
View user's profile Send private message
downey
Tux's lil' helper
Tux's lil' helper


Joined: 17 Nov 2004
Posts: 107
Location: Calgary, Canada

PostPosted: Tue Aug 01, 2006 1:42 am    Post subject: Reply with quote

Well it depends on your definition of emulation. Really the chip just converts, in hardware, the instructions into 64 bit instructions. As far as I've seen the AMD64 chips can run 32-bit code just as fast as any other chip. You do get some performance improvement using 64-bit instructions but the improvement is really seen when you go past the 4 Gigabyte memory boundry of 32-bit systems or do a lot of 64-bit math. So realistically you won't see any huge improvement by going all 64-bit until programs get reworked to use the advantages of the 64-bit architecture. Right now there aren't many programs that would really benifit from it, but there are a few.

The future is 64-bit so I would definitely encourage you to stick with 64-bit with multilib support. Really the only program that I have that I explicitly have to get 32-bit is Firefox and that is only due to flash being only 32-bit. Also some Windows only video formats won't work without some workarounds.

Hope that helps.
Back to top
View user's profile Send private message
Phenax
l33t
l33t


Joined: 10 Mar 2006
Posts: 972

PostPosted: Tue Aug 01, 2006 3:21 am    Post subject: Reply with quote

I've had a amd64 for a couple of years. Two different socket/models.

A few tips.

  • add
    Code:
    -msse3
    cflag if your processor is Socket 939 (Excluding the Winchester models), or Socket AM2.. Don't know about Intel.

    If your unsure do a
    Code:
    cat /proc/cpuinfo | grep pni
    and if anything comes up you have SSE3
  • Forget flash and use x86_64 firefox. Flash is a piece of junk and we aren't even getting any updates. It's in the works, but so is Duke Nukem Forever.
  • If your not really afraid, I suggest running a ~amd64 system. I've been running one for about a year now with minimal problems. ~amd64 usually has more amd64 compatibility.


I usually do a Stage 1, they still have the tarbells up and there's a how-to on gentoo-wiki.com. All you have to do extra is bootstrap (Run a script) really.

x86 emulation is flawless everytime I use it.

You can enable it in the kernel under
Code:
Executable file formats / Emulations
and put a * (Build in) next to ia32 emulation and ia32 a.out support.

It should be on by default, though.

Hope you enjoy.
Back to top
View user's profile Send private message
s.j.o
n00b
n00b


Joined: 03 May 2006
Posts: 8

PostPosted: Tue Aug 01, 2006 5:49 pm    Post subject: Reply with quote

This one is a little outdated, but it has a link to a maintained version. It should still be the same process, more or less.
https://forums.gentoo.org/viewtopic-t-400576.html
It's not much more than installing a stage 3, configuring the system to your liking, and recompiling everything. But it's a good guide, worth following the first few installs you do.

It is, however, more than just one emerge -vuDe world -- that may get you by, and work completely for some people, but it doesn't ensure that the toolchain and base packages are consistent - and if they break, you'll probably be reinstalling.

Quote:

Also, as long as I don't get the no-multilib version, I should have support for 32bit emulation by default, right?

Technically, there isn't a no-multilib version to get: the multilib stuff is controlled in your settings. In particular, by your choice of profile:
Code:

~ $ ls -l /etc/make.profile
lrwxrwxrwx 1 root root 50 Jun 13 07:37 /etc/make.profile -> ../usr/portage/profiles/default-linux/amd64/2006.0

That is the default profile for amd64, which includes multilib ---> includes 32-bit support.
The only other thing about the 32-bit emulation is the packages like emul-linux-x86-compat, but they should be installed as dependencies automagically by portage, for example, if you did an emerge mplayer-bin.
In short, 32-bit support is on by default. :) It's just not such a pain anymore.

@downey:
On a stage 3 the CHOST should already be set to x86_64-pc-linux-gnu, IIRC (as long you download the amd64 tarball)
Back to top
View user's profile Send private message
Display posts from previous:   
Reply to topic    Gentoo Forums Forum Index Gentoo on AMD64 All times are GMT
Page 1 of 1

 
Jump to:  
You cannot post new topics in this forum
You cannot reply to topics in this forum
You cannot edit your posts in this forum
You cannot delete your posts in this forum
You cannot vote in polls in this forum