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/
Home Products Support Community News


RE: [Xen-devel] Poor performance on HVM (kernbench)

To: deshantm@xxxxxxxxx
Subject: RE: [Xen-devel] Poor performance on HVM (kernbench)
From: Daniel Magenheimer <dan.magenheimer@xxxxxxxxxx>
Date: Wed, 10 Sep 2008 14:45:26 -0700 (PDT)
Cc: xen-devel mailing list <xen-devel@xxxxxxxxxxxxxxxxxxx>
Delivery-date: Wed, 10 Sep 2008 14:46:37 -0700
Envelope-to: www-data@xxxxxxxxxxxxxxxxxxx
In-reply-to: <1e16a9ed0809101442q225c5fcfj25c0b4ffe0da83a0@xxxxxxxxxxxxxx>
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>
Sender: xen-devel-bounces@xxxxxxxxxxxxxxxxxxx
Perhaps you should run the native with nosmp then, to ensure
the comparison isn't taken out of context.

> -----Original Message-----
> From: Todd Deshane [mailto:deshantm@xxxxxxxxx]
> Sent: Wednesday, September 10, 2008 3:42 PM
> To: Daniel Magenheimer
> Cc: xen-devel mailing list
> Subject: Re: [Xen-devel] Poor performance on HVM (kernbench)
> On Wed, Sep 10, 2008 at 5:37 PM, Daniel Magenheimer
> <dan.magenheimer@xxxxxxxxxx> wrote:
> > This doesn't answer the HVM question but it appears that
> > you are running guests with 1 vCPU but comparing against
> > a dual-CPU native.  True?
> Yes. The intuition is that we don't want to overcommit virtual CPUs
> since then you are stressing the schedulers more.
> I ran some tests with 2 vCPUs and all the numbers are a bit higher (as
> having two CPUs tackling a compile is faster).
> Although overcommit (of CPUs and memory ;) is interesting, we leave a
> CPU dedicated to the host system (linux/dom0)
> on purpose.
> Todd
> _______________________________________________
> Xen-devel mailing list
> Xen-devel@xxxxxxxxxxxxxxxxxxx
> http://lists.xensource.com/xen-devel

Xen-devel mailing list