[Gllug] Hardware problems / good replacements

Phil Reynolds phil-gllug at tinsleyviaduct.com
Sat Feb 11 18:47:06 UTC 2012

On 11/02/12 12:00, Richard W.M. Jones wrote:
> I'm surprised that a BIOS update made any difference.  I wasn't aware
> that virtualization extensions could be disabled on AMD; on Intel it
> is (or used to be) a problem that virtualization would be disabled by
> the BIOS and couldn't be reenabled, requiring a BIOS update or even a
> replacement motherboard to rectify.  Perhaps the BIOS update just
> fixed some clock speed or memory settings, making the machine
> generally faster.

Well, it could be switched off, but to my knowledge it was always on.

> It's academic now, but before the BIOS update did you check the
> obvious stuff; all cores enabled? core speed? BogoMIPS? memory
> settings set for maximum performance ...?

Checked the lot - if anything, attempting to improve performance made it
even worse.

>>> The second problem is Debian squeeze ... because it's old.  Using the
>>> latest kernel, qemu-kvm and libvirt should yield significantly better
>>> results.
>> I tried a later qemu-kvm... it didn't seem to make much difference on
>> what I could actually get it to do at the time. I will try it again
>> fairly soon, if this problem persists.
> You need to upgrade the whole stack, from kernel up through userspace
> tools.  This needs coordination from all components.

I will consider that before expecting miracles. If I recall correctly,
libvirt was the most daunting to deal with.

> Also check that KVM is actually being used.  You should see the
> 'kvm_amd' module is loaded, and there should be no warnings or errors
> in 'dmesg' about virtualization being disabled.

That was the first thing I checked. Nothing ever appeared to be going
wrong with it.

Phil Reynolds
mail: phil-gllug at tinsleyviaduct.com
Gllug mailing list  -  Gllug at gllug.org.uk

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