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-users

[Xen-users] Floating Processors

To: xen-users@xxxxxxxxxxxxxxxxxxx
Subject: [Xen-users] Floating Processors
From: Dylan Martin <dmartin@xxxxxxxxxxxx>
Date: Wed, 18 Apr 2007 12:53:53 -0700
Delivery-date: Wed, 18 Apr 2007 12:52:40 -0700
Envelope-to: www-data@xxxxxxxxxxxxxxxxxx
List-help: <mailto:xen-users-request@lists.xensource.com?subject=help>
List-id: Xen user discussion <xen-users.lists.xensource.com>
List-post: <mailto:xen-users@lists.xensource.com>
List-subscribe: <http://lists.xensource.com/cgi-bin/mailman/listinfo/xen-users>, <mailto:xen-users-request@lists.xensource.com?subject=subscribe>
List-unsubscribe: <http://lists.xensource.com/cgi-bin/mailman/listinfo/xen-users>, <mailto:xen-users-request@lists.xensource.com?subject=unsubscribe>
Sender: xen-users-bounces@xxxxxxxxxxxxxxxxxxx
User-agent: Mutt/1.4.2.2i
If the CPUs are "floating" as opposed to "pinned", it's possible for a
busy VM to use all the available processors if the other VMs are idle,
right?  

E.G., if I have 4 CPUs and 3 VMs and none of my CPUs are pinned, and
one of my VMs is compiling a kernel while the other two are idle, the
busy kernel-compiling VM will use all 4 CPUs, right?  It won't be
limted to only 2 or something, right?

I'm curious because I've noticed a few people and documents mention
pinning one cpu to each VM.  

I assume is is because they don't want a situation where a
low-priority but high-processor-usage task on one VM causes another VM
with a sporadic but high-priority job to hang out waiting for the
low-prioroty job to finish.  

Ok, now that I've read my own question, I guess my real question is, 
can someone point me to a good document that descibes how Xen allocates 
available processors..?  If there isn't such a document, please take a
shot at the question above...

Thanks!
-Dylan

_______________________________________________
Xen-users mailing list
Xen-users@xxxxxxxxxxxxxxxxxxx
http://lists.xensource.com/xen-users

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