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-users] What's the different for "dom0_max_vcpus=4dom0_vcpus_pin

To: Robert Dunkley <Robert@xxxxxxxxx>
Subject: Re: [Xen-users] What's the different for "dom0_max_vcpus=4dom0_vcpus_pin" and "dom0_max_vcpus=4" ?
From: lei yang <yanglei.fage@xxxxxxxxx>
Date: Fri, 21 May 2010 23:38:22 +0800
Cc: xen-devel@xxxxxxxxxxxxxxxxxxx, Xen Mailing List <xen-users@xxxxxxxxxxxxxxxxxxx>
Delivery-date: Fri, 21 May 2010 08:40:05 -0700
Dkim-signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=gmail.com; s=gamma; h=domainkey-signature:mime-version:received:received:in-reply-to :references:date:message-id:subject:from:to:cc:content-type; bh=XppnazbNDcvnvfB7Jb94BDIX9Ad9n2rKaMrmcLcRClQ=; b=bsA+/ywfl9iZsnA9rh1ENT5Kx7XWB3RZ0JAdsVWgu6E2RiyP9/mEqJsEJrvbJpXpx9 fs/bfCGtp2/VyzDcfjKeHh+KkJuc6F+1q8kZruIK8UqpCuFkNuvYBo5jyLcIVr/NGgCU fzKllcX78pYn3UOEnZfrYxRugmV78gqNCZnro=
Domainkey-signature: a=rsa-sha1; c=nofws; d=gmail.com; s=gamma; h=mime-version:in-reply-to:references:date:message-id:subject:from:to :cc:content-type; b=XMqPYECHIWZ53lw5qM83+059a8vnnmSq0KfI3IhuD/yY2RAV9I6lUIDUH6DSTdeMRL Aw2fH+HZzGbXanjWI+4Azosf+li6OyqOCA1V7bfgkF/rnn6jt3UOxIRdXCODe+cH6NQb Hn5n8bQGdQfNIDZKoui+MVPWCS9HbsTv/Mxf8=
Envelope-to: www-data@xxxxxxxxxxxxxxxxxxx
In-reply-to: <C1EAC9C5E752D24C968FF091D446D82360D244@ALTERNATEREALIT>
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/mailman/listinfo/xen-users>, <mailto:xen-users-request@lists.xensource.com?subject=subscribe>
List-unsubscribe: <http://lists.xensource.com/mailman/listinfo/xen-users>, <mailto:xen-users-request@lists.xensource.com?subject=unsubscribe>
References: <AANLkTik4TnkY-uGfhW5sbPwG5U1msw_eVt5X1j0IDdBD@xxxxxxxxxxxxxx> <C1EAC9C5E752D24C968FF091D446D82360D244@ALTERNATEREALIT>
Sender: xen-users-bounces@xxxxxxxxxxxxxxxxxxx


On Fri, May 21, 2010 at 8:02 PM, Robert Dunkley <Robert@xxxxxxxxx> wrote:

Hi Lei,

 

 

Q1: The pin is needed to lock Dom0 to cores 0 & 1.

 

dom0_max_vcpus=4 dom0_vcpus_pin just lock Dom0 to cores0 and 1?? but it's "4"
 

Q2: It means 4 vcpus are allocated to Dom0, they can float between physical cores.

 
dom0_max_vcpus=4 , can be the 4 cores=2 3 4 5, does it will change to 1 2 3 4? or just bind to 2 3 4 5
dom0_max_vcpus=4 dom0_vcpus_pin will just to core0-3?

VCPUs don’t really line up with cores, you can assign 8 vcpus on a DomU  on a 4 core Dom0 box for example. 8 cpus will appear in the VM but Xen will try to allocate the request within its 4 physucal cores. Generally assigning more VPUs than you have physical cores is pointless.

 

Q3: No SMP for a DOMU will mean the kernel is not SMP aware, this can save a small amount of overhead and improve scheduling in certain cases on a single core DOMU. I’m not sure what the affect would be on Dom0, my guess is it won’t be good.

 

 

 

Rob

 

From: xen-users-bounces@xxxxxxxxxxxxxxxxxxx [mailto:xen-users-bounces@xxxxxxxxxxxxxxxxxxx] On Behalf Of lei yang
Sent: 21 May 2010 04:09
To: Xen Mailing List; xen-devel@xxxxxxxxxxxxxxxxxxx
Subject: [Xen-users] What's the different for "dom0_max_vcpus=4dom0_vcpus_pin" and "dom0_max_vcpus=4" ?

 

Hi experts,


Q1:What's the different for "dom0_max_vcpus=4 dom0_vcpus_pin" and  "dom0_max_vcpus=4" ?
which will get better performance

Q2: dom0_max_vcpus=4 means "core0-3 will be just used by dom0" or means "4 cores(not dedicate cores) will be used by dom0, eg: core2-5 or core3-6?

Q3.what does mean "nosmp" , xen, dom0,domU, will just use one core????if so, can we specify the use different core. eg: dom0=core2 domU=core3? xen will use just one core?

Thanks
Lei








--
"We learn from failure, not from success!"

The SAQ Group

Registered Office: 18 Chapel Street, Petersfield, Hampshire GU32 3DZ
SAQ is the trading name of SEMTEC Limited. Registered in England & Wales
Company Number: 06481952

 

http://www.saqnet.co.uk AS29219

SAQ Group Delivers high quality, honestly priced communication and I.T. services to UK Business.

Broadband : Domains : Email : Hosting : CoLo : Servers : Racks : Transit : Backups : Managed Networks : Remote Support.

 

 SAQ Group

 

ISPA Member




--
"We learn from failure, not from success!"
_______________________________________________
Xen-users mailing list
Xen-users@xxxxxxxxxxxxxxxxxxx
http://lists.xensource.com/xen-users