Successful 64-bit installation on a EM64T Xeon

[z-buffer]

Hi all,

I just wanted to let you know: We succeeded in installing a 64-bit-Gentoo (2005.0) on a Dell PowerEdge 1800 machine (Intel Xeon 2.8 GHz EM64T, 2GB RAM, ...). We booted off the AMD64 disc and used the 'gentoo' kernel, as 'gentoo-em64t' is not available by now (Bug). These are our CHOST and [C|CXX]FLAGS settings:

[azlan]

do you have any extra, of those laying around???
_________________
there is no crazy, only violet and non violet..

[z-buffer]

I'm afraid not ... we have to work with these from time to time.

[mr.ed]

Hey,

Congrats on your first install on a em64t system, but i've got a question for u:

[z-buffer]

Hi,

I would love to see a listing of all implications and dependencies of all those potential CFLAGS one could use. We actually used ours the mentioned way to make sure the processor extensions are really used for floating point math and the like. We derived the flags from several forum posts and this Intel presentation on EM64T performance.
The march setting usually *should* imply those settings, yes. If it does, I don't know. I have no idea how to check whether the flags are being used in the installed system, too.

[mr.ed]

Hey Alex,

As u requested, here's the link to the gcc manual :

[z-buffer]

Thanks for the link, Ed. That is indeed a good starting point for optimization flags, although the dependencies are still not perfectly clear ...
As far as I understand the listing, the only compiler flags implicitly set on our machines are:

• -mtune=nocona by setting -march=nocona
  
• -mfpmath=sse, -msse, & -msse2 by using a x86_64 compiler
  

[piramid]

I have interest in know if Apache2+PHP5 and Qmail+Vpopmail runs fine in EM64T. Somebody has tried it?

[z-buffer]

We are running Apache2 with mod_PHP 4 on our EM64T Xeon. That works without any problems.

[piramid]

[mr.ed]

Hey Alex,

Sorry for the delay in reaction to your post. As for your findings, the way i looked at it (and i do agree the manual is a bit vague on the subject) setting -march=nocona is enough to enable the instructionset specific for this type of processor.
If u look up the nocona flag in the manual it states:

[z-buffer]

According to the GCC manual, the -mtune flag tunes for everything "except for ... the set of available instructions". The -march flag on the other hand "generates instructions" for the specified cpu. So, -march creates code that *requires* the given processor at runtime, whereas -mtune merely optimizes code to the given processor while still being portable to others.

After even more googling I still haven't found any serious link that explicitly documents the redundancy of the -mmmx and -msse3 flags when using -march=nocona. Even the Intel presentation on optimization of EM64T systems I mentioned in an earlier post, uses the -msse3 flag. So unless otherwise explicitly proven, I will continue to use -mmmx and -msse3.

[piramid]

I'm trying to boot from CD Universal disk amd 64 on PowerEdge 1850 and when select Gentoo kernel starts load kenel and then black screen and freezes. Is a two cpu 3.0 with 1GB of ram.

Suggestions ?

[mr.ed]

Just use the k8-kernel in the cd, the em64t kernel is b0rked!!
_________________
(Ex-Pornstar)

[piramid]

[mr.ed]

That was when using the em64t-kernel on the livecd or the k8 one? Sounds like a corrupt iso to me otherwise.. Try re-downloading it otherwise..
_________________
(Ex-Pornstar)

[stillman]

i'll have to install a em64t-xeon-dual(nocona) server on friday. it's main task will be to serve as a asterisk-media-gateway. since i've got absolutely no experience with the whole 64bit architecture resp. architectures per se i'm pretty unsure if the installation will run smooth. my main concern is the stable and flawless function of the installed packages. can someone proof(or at least suggest) that asterisk or other amd64-ebuilds will compile and work properly on a em64t installed with the nocona-flag resp. with a amd64-based installation? or would you recommend to run a simple Pentium4-x86-installation to be sure there'll be no trouble?

[DangerDan]

since you're going to be using it as an astrisk server, you want it to be as stable as possible - i'd steer clear of the 64 bit compile. the amd64 2005.0 install uses gcc 3.4.x by default. i prefer to use 3.3.x for boxes that i need to be solid. just mho.

[stillman]

thanks for pointing me there - indeed there seem to be issues when compiling asterisk with gcc-3.4, having searched google for info on that matter. guess i'll stick to x86 for the time beeing. i assume to use standard pentium4 cflags then.

[petrjanda]

Im trying LFS and I think this is a gentoo related problem. Im running in 64-bits.

[jannis]

I tried to boot a Pentium4 EM64T from the AMD64-CD and it just rebooted after having loaded the kernel and the initrd to RAM. The machine has 2GB RAM. I tried the "gentoo" (k8) kernel and the gentoo-em64t but non of them worked. The thing just reboots.
Anyone got an idea?

[dildassen]

Just thought I'd let you guys know that the AMD64 stage1 install worked flawlessly on my Poweredge 2850 servers, 2 x dual Xenon 64bit, 6Gmem, SCSI RAID etc....

[Vampire999]

When you guys were up and running off your own kernel did it show two cpus or four?

When I was running from the cd it showed me there were four. Now that I have compiled the 2.6.12 kernel specifying the "Intel em64t" I only see two cpu's.