Re: [Xen-users] 2 DomU and 2 4-cores CPU

[Michael Schmidt <michael.schmidt@xxxxxxxxxx>]

Hi,

Xen has different CPU schedulers. The default is the credit scheduler - 
this is a "fair" scheduler.
Here cou can read more about it:

http://wiki.xensource.com/xenwiki/CreditScheduler

Mit freundlichen Gruessen / Best Regards

Michael SchmidtAm 09.04.10 09:09, schrieb L.M.J:        

> On Fri, 02 Apr 2010 10:29:53 +0200, Michael Schmidt
> <michael.schmidt@xxxxxxxxxx>  wrote:
>    
> > Hi,
> >
> > you can assign all DomUs all cores.
> > In the case of 100% utilization of both DomUs, the xen-scheduler
> > provides 50% CPU time from all the CPUs for each DomU.
> > If one DomU idles and the other one, need 100% CPU, it will get the
> > power of all the 8 Cores.
> >      
> Thanks Michael for your fast reply. I would like to share what I've heard
> from Vmware : when you assigned 4 CPU to a VM, Vmware wait to have 4 cores
> free at the same time before give them to the VM which could slow down your
> VM instead of speed up.
> Is there the same issue with Xen ?
>
>
>    
> > L.M.J schrieb:
> >      
> > > Hi,
> > >
> > >    With my college, I was wondering what is the best optimization for our
> > > setup. I've got 2 VM with 16GB of RAM and 4 vCPU to each one. My server
> > > got 2 CPU with 4 cores inside (makes 8 CPU). What produce the best
> > > performance :
> > >    1) Give ALL cpu to my 2 VM and each ones will take its 4 vCPU where it
> > >        
> can
>    
> > >    2) Give CPU 0-3 to VM1 and CPU 4-7 to VM2 : each vm own the 4 cores
> > >        
> from 1 CPU
>    
> > >    3) Give CPU 0,1,4,5 to VM1 and 2,3,6,7 to VM2 : mix cores  between the
> > >        
> both CPU
>    
> > >    Thanks by advance for any information or point me to any docs talking
> > >        
> about this !
>
>    
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