Arch Linux

tonyar

Member

Registered: 2009-03-19

Posts: 3

2 x Quad Core Zeon / 8GB RAM - not seeing all ram or CPUs

I have just installed Arch on an HP XW6400 workstation, with dual quad Zeons and 8GB ram.

However, the kernel is only seeing 1 (quad) CPU and also only seeing 4gb ram.

Output from uname -a is:

Linux vm-test 2.6.24-ARCH #1 SMP PREEMPT Sun Mar 30 11:40:06 CEST 2008 i686 Intel(R) Xeon(R) CPU E5320 @ 1.86GHz GenuineIntel GNU/Linux

[root@vm-test /]# cat /proc/meminfo
MemTotal:      3369076 kB
<snip>

Summary from "top"

Cpu0  :  0.0%us,  0.0%sy,  0.0%ni,100.0%id,  0.0%wa,  0.0%hi,  0.0%si,  0.0%st
Cpu1  :  0.0%us,  0.0%sy,  0.0%ni,100.0%id,  0.0%wa,  0.0%hi,  0.0%si,  0.0%st
Cpu2  :  0.0%us,  0.0%sy,  0.0%ni,100.0%id,  0.0%wa,  0.0%hi,  0.0%si,  0.0%st
Cpu3  :  0.0%us,  0.0%sy,  0.0%ni,100.0%id,  0.0%wa,  0.0%hi,  0.0%si,  0.0%st
Mem:   3369076k total,   146524k used,  3222552k free,    41444k buffers
Swap:  4200988k total,        0k used,  4200988k free,    69144k cached

Do I need to recompile the kernel to enable the additional CPUs and RAM?

I previously had Server 2003 installed in this box, and that saw all 8 CPUs and 8gb ram.

I seem to recall that RedHat / CentOS have a "bigmem" kernel for situations such as this - but I cannot seem to find any reference to such a kernel in the Arch Wiki / Software repository or forums.

Thanks,
Tony.

edit: corrected my bad spelling

Last edited by tonyar (2009-03-19 11:02:55)

Runiq

Member

From: Germany

Registered: 2008-10-29

Posts: 1,053

Re: 2 x Quad Core Zeon / 8GB RAM - not seeing all ram or CPUs

Linux vm-test 2.6.24-ARCH #1 SMP PREEMPT Sun Mar 30 11:40:06 CEST 2008 i686

Did you do an i686 or an x86_64 installation? Looks like the former to me, which might explain why Arch is not seeing all of your RAM. Installing 64-bit Arch will solve this, though I'm not sure about the core problem...

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Dotfiles

tonyar

Member

Registered: 2009-03-19

Posts: 3

Re: 2 x Quad Core Zeon / 8GB RAM - not seeing all ram or CPUs

I did an i686 installation, as I have a specific requirement for 32 bit.

I just did a full system update, and now all 8 CPUs are visible - but still 4gb ram

Cpu0  :  0.0%us,  0.0%sy,  0.0%ni,100.0%id,  0.0%wa,  0.0%hi,  0.0%si,  0.0%st
Cpu1  :  0.0%us,  0.0%sy,  0.0%ni,100.0%id,  0.0%wa,  0.0%hi,  0.0%si,  0.0%st
Cpu2  :  0.0%us,  0.0%sy,  0.0%ni,100.0%id,  0.0%wa,  0.0%hi,  0.0%si,  0.0%st
Cpu3  :  0.0%us,  0.0%sy,  0.0%ni,100.0%id,  0.0%wa,  0.0%hi,  0.0%si,  0.0%st
Cpu4  :  0.0%us,  0.0%sy,  0.0%ni,100.0%id,  0.0%wa,  0.0%hi,  0.0%si,  0.0%st
Cpu5  :  0.0%us,  0.3%sy,  0.0%ni, 99.7%id,  0.0%wa,  0.0%hi,  0.0%si,  0.0%st
Cpu6  :  0.0%us,  0.0%sy,  0.0%ni,100.0%id,  0.0%wa,  0.0%hi,  0.0%si,  0.0%st
Cpu7  :  0.0%us,  0.0%sy,  0.0%ni,100.0%id,  0.0%wa,  0.0%hi,  0.0%si,  0.0%st
Mem:   3375116k total,    47140k used,  3327976k free,     4424k buffers
Swap:  4200988k total,        0k used,  4200988k free,    16864k cached

I'm sure it's possible for a 32bit kernel to see all 8gb ram?

Thanks,
Tony.

lucke

Member

From: Poland

Registered: 2004-11-30

Posts: 4,018

Re: 2 x Quad Core Zeon / 8GB RAM - not seeing all ram or CPUs

You probably have to recompile the kernel with HIGHMEM64G enabled.

bangkok_manouel

Member

From: indicates a starting point

Registered: 2005-02-07

Posts: 1,556

Re: 2 x Quad Core Zeon / 8GB RAM - not seeing all ram or CPUs

Definitely.
http://repos.archlinux.org/viewvc.cgi/k … sion=29572 says:
CONFIG_HIGHMEM4G=y
# CONFIG_HIGHMEM64G is not set

tonyar

Member

Registered: 2009-03-19

Posts: 3

Re: 2 x Quad Core Zeon / 8GB RAM - not seeing all ram or CPUs

Yes - a kernel rebuild has done the trick.

I kinda guessed the HIGHMEM option was set to 4gb, but wanted to be sure (and didn't even think of checking .config !)

Also surpised that a "BIGMEM" kernel is not avaible as default, given the falling price of memory.

Thanks for all the responses.

Tony.

Last edited by tonyar (2009-03-19 14:05:36)

KimTjik

Member

From: Sweden

Registered: 2007-08-22

Posts: 715

Re: 2 x Quad Core Zeon / 8GB RAM - not seeing all ram or CPUs

Since you deal with a hardware limit of x86 32bit I don't see a reason for having a technological workaround implemented by default. As far as I understand you'll get a cleaner 32bit environment by not enabling it - it works according to its hardware - but if you need to bypass this limit it's possible to enable that "HIGHMEM" feature.

Too bad though that some software still isn't available for 64bit.

bangkok_manouel

Member

From: indicates a starting point

Registered: 2005-02-07

Posts: 1,556

Re: 2 x Quad Core Zeon / 8GB RAM - not seeing all ram or CPUs

you could also install a 64bit kernel (and kernel only), works great (so far).
http://bbs.archlinux.org/viewtopic.php?id=66660

ckristi

Member

From: Bucharest, Romania

Registered: 2006-11-21

Posts: 225

Re: 2 x Quad Core Zeon / 8GB RAM - not seeing all ram or CPUs

I'm running Slackware (which is a 32bit distro for the moment) with HIGHMEM64 enabled as my Backup server (RAID1+SSH&rsync&Samba) for quite some time now and everything works flawlessly. As far as I know there is a slight performance impact if using HIGHMEM64, but with the newer processors (I think even a Pentium4 at 1.0GHz would have an unnoticeable performance impact) you just cannot see any real difference if you're not a "benchmark all you can" kind of guy/girl.

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In love I believe and in Linux I trust