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] What's the different for "dom0_max_vcpus=4 dom0_vcpus_p

To: Keir Fraser <keir.fraser@xxxxxxxxxxxxx>
Subject: Re: [Xen-devel] What's the different for "dom0_max_vcpus=4 dom0_vcpus_pin" and "dom0_max_vcpus=4" ?
From: lei yang <yanglei.fage@xxxxxxxxx>
Date: Fri, 21 May 2010 23:39:50 +0800
Cc: "xen-devel@xxxxxxxxxxxxxxxxxxx" <xen-devel@xxxxxxxxxxxxxxxxxxx>, Xen Mailing List <xen-users@xxxxxxxxxxxxxxxxxxx>
Delivery-date: Fri, 21 May 2010 08:43:20 -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=w0lkzx2QM3ge2wMbEOEMt0VBXiLuNViBZYgp26N3Y74=; b=iLuiChy3EHpgojdvoHu59u1xhF0U5e2ZBJzqLHHWZOF7+36IuabmGRETBGouAzq9sd 1EeaJH6qU1Iwr6Mn0hwEJt+WKCwyZ3ChdMh/4mGw70vyXGqeqpZAvRy3aCxjO4U0xdzn SvC6mOcHlTlUxtj+WpT1R+5pZWLcpcZjoT/CQ=
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=F+crUfMTfcTPH4vEz4afWZ0s+iA6/JQhPdroTWoecffc/A/505uycKgiJQPrVue/w6 iH4JNmgSLz+IhT6tek8WI3zQLVxwAhi7okjRXxfkl/LKsq3KR9lGrS3OlsvfGIx4vJji n4QWV851MTb2b7vAqmHK1BBFRjfsNDSSijpeM=
Envelope-to: www-data@xxxxxxxxxxxxxxxxxxx
In-reply-to: <C81BED7E.14B7E%keir.fraser@xxxxxxxxxxxxx>
List-help: <mailto:xen-devel-request@lists.xensource.com?subject=help>
List-id: Xen developer discussion <xen-devel.lists.xensource.com>
List-post: <mailto:xen-devel@lists.xensource.com>
List-subscribe: <http://lists.xensource.com/mailman/listinfo/xen-devel>, <mailto:xen-devel-request@lists.xensource.com?subject=subscribe>
List-unsubscribe: <http://lists.xensource.com/mailman/listinfo/xen-devel>, <mailto:xen-devel-request@lists.xensource.com?subject=unsubscribe>
References: <AANLkTik4TnkY-uGfhW5sbPwG5U1msw_eVt5X1j0IDdBD@xxxxxxxxxxxxxx> <C81BED7E.14B7E%keir.fraser@xxxxxxxxxxxxx>
Sender: xen-devel-bounces@xxxxxxxxxxxxxxxxxxx


On Fri, May 21, 2010 at 2:57 PM, Keir Fraser <keir.fraser@xxxxxxxxxxxxx> wrote:
On 21/05/2010 04:09, "lei yang" <yanglei.fage@xxxxxxxxx> wrote:

> 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

The former restricts Xen to only run Dom0 VCPUs 0-3 on physical CPUs 0-3.
 
dom0_max_vcpus=4 dom0_vcpus_pin will just to core0-3? can it be 3 4 5 6?
if remove "dom0_vcpus_pin" just use "  dom0_max_vcpus=4 " can it be 3 4 5 6 ?
 
It's not really a performance thing, but instead is to mean that some things
like cpufreq management can work directly from dom0. We don't really use the
dom0_vcpus_pin option much.

> 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?

Dom0's VCPUs can be scheduled on any physical CPU at any time, unles
dom0_vcpus_pin is specified.

> 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?

It brings Xen up on the boot CPU only. Nothing in the system will use the
other CPUs. You don't want to use this option really.

 -- Keir





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