WARNING - OLD ARCHIVES

This is an archived copy of the Xen.org mailing list, which we have preserved to ensure that existing links to archives are not broken. The live archive, which contains the latest emails, can be found at http://lists.xen.org/
   
 
 
Xen 
 
Home Products Support Community News
 
   
 

xen-devel

Re: [Xen-devel] SMP guest support in unstable tree.

On Wed, 5 Jan 2005, Christian Limpach wrote:

> On Wed, Jan 05, 2005 at 09:06:10AM -0600, Andrew Theurer wrote:
> > >I don't think there's significant overhead if there's only a single
> > >virtual cpu pinned to one physical cpu so I wouldn't expect a noticeable
> > >performance advantage if we handled this case differently.
> > >
> > Hopefully soon I can get some performance tests going and we can see if
> > there's any issues here.  My other concern would be on larger (multi
> > numa-node) systems, even with one to one mapping, that the hardware
> > topology (numa) information does not make it to the SMP guest -it would
> > be nice to take advantage of the numa work developed in the linux kernel
> > over that last 2 years.  I am not sure exactly what impact this could be.
>
> Yes, this is probably even needed on 2-cpu with 2 hyperthreads systems.
> Right now, all virtual cpus are presented as independent physical cpus
> to the domains and the domains can't easily tell if two virtual cpus
> run on different physical cpus, on different hyperthreads on the same
> cpu or on the same hyperthread.  If we export this information to the
> guest, we'll then probably also have to have a way to inform the guest
> if a virtual cpu is moved to a different hyperthread or physical cpu.

Also consider the NUMA equation.

Search l-k for cpusets.


-------------------------------------------------------
The SF.Net email is sponsored by: Beat the post-holiday blues
Get a FREE limited edition SourceForge.net t-shirt from ThinkGeek.
It's fun and FREE -- well, almost....http://www.thinkgeek.com/sfshirt
_______________________________________________
Xen-devel mailing list
Xen-devel@xxxxxxxxxxxxxxxxxxxxx
https://lists.sourceforge.net/lists/listinfo/xen-devel

<Prev in Thread] Current Thread [Next in Thread>