Virtualization Status on Wilbur

[Matt Hogstrom <ma...@hogstrom.org>]

I've got an 8-way Intel system with 20GB of memory I've been playing  
around with so see if I can virtualize it for some clustering  
experiments as well as a general build machine.  I've talked to  
people individually but I don't think I mentioned anything on the  
list.  Its not a clandestine effort so I thought I'd pop a quick  
status out to the list so people know what's going on.  If people  
want to see intermediate status notes I'm happy to provide them but  
don't want to put out a set of notes that most people send to /dev/ 
null so comment back if your interested.  If there are no responses  
indicating interest I'll take silence to mean no real interest, which  
is fine.

Right now I'm running SuSE Open Linux 10.2 with the Xen kernel.  I've  
created a VM with 3G of memory and 2 CPUs (I don't currently have  
Intel hyperthreading enabled).

The performance of the VM is a bit sluggish.  I had made some  
assumptions on the performance based on the box's characteristics (4  
3.4Ghz dual core processors with 16MB shared L3 cache).  It has 20GB  
of PC3200 memory.  I think those assumptions may not be valid so I'm  
going to step backand get a baseline of native performance and then  
layer in the Xen Kernel and finally some VMs.  I was hoping to avoid  
these steps cause they take time.

In any event, Joe, let's step back.  I'm going to move your home dir  
from vm01 back to wilbur (everything should still run fine) and  
reboot native.  Le'ts see where that get's us.

Cheers. 

Re: Virtualization Status on Wilbur

[Matt Hogstrom <ma...@hogstrom.org>]

On Mar 4, 2007, at 3:25 PM, Jeff Genender wrote:

>
>
> Matt Hogstrom wrote:
>> Right now I'm running SuSE Open Linux 10.2 with the Xen kernel.  I've
>> created a VM with 3G of memory and 2 CPUs (I don't currently have  
>> Intel
>> hyperthreading enabled).
>>
>> The performance of the VM is a bit sluggish.  I had made some
>> assumptions on the performance based on the box's characteristics (4
>> 3.4Ghz dual core processors with 16MB shared L3 cache).  It has  
>> 20GB of
>> PC3200 memory.  I think those assumptions may not be valid so I'm  
>> going
>> to step backand get a baseline of native performance and then  
>> layer in
>> the Xen Kernel and finally some VMs.  I was hoping to avoid these  
>> steps
>> cause they take time.
>
> Look in to tuning the kernel and Xen, and th eprocessor.

Looking at that now. Thanks

> I have seen
> virtualization, when tuned, to nearly see almost no performance
> difference.  Also be sure you boot into the bios and turn on the VT
> processor extensions.  A larges % of the machines get shipped with  
> those
> turned off in the bios (I don't know why they keep em off initially).

First thing I did :)  I also disable hyperthreading for now as I'm  
thinking that Xen most likely doesn't differentiate between a  
hyperthreaded processor and a fully core.

>
> Jeff
>

Re: Virtualization Status on Wilbur

[Jeff Genender <jg...@apache.org>]

Matt Hogstrom wrote:
> Right now I'm running SuSE Open Linux 10.2 with the Xen kernel.  I've
> created a VM with 3G of memory and 2 CPUs (I don't currently have Intel
> hyperthreading enabled).
> 
> The performance of the VM is a bit sluggish.  I had made some
> assumptions on the performance based on the box's characteristics (4
> 3.4Ghz dual core processors with 16MB shared L3 cache).  It has 20GB of
> PC3200 memory.  I think those assumptions may not be valid so I'm going
> to step backand get a baseline of native performance and then layer in
> the Xen Kernel and finally some VMs.  I was hoping to avoid these steps
> cause they take time.

Look in to tuning the kernel and Xen, and th eprocessor.  I have seen
virtualization, when tuned, to nearly see almost no performance
difference.  Also be sure you boot into the bios and turn on the VT
processor extensions.  A larges % of the machines get shipped with those
turned off in the bios (I don't know why they keep em off initially).

Jeff