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

Re: [Xen-users] Gigabit Interface - XEN Full Virtualization

To: xen-users@xxxxxxxxxxxxxxxxxxx
Subject: Re: [Xen-users] Gigabit Interface - XEN Full Virtualization
From: Mark Williamson <mark.williamson@xxxxxxxxxxxx>
Date: Sun, 2 Dec 2007 02:34:43 +0000
Cc: Sadique Puthen <sputhenp@xxxxxxxxxx>, Artur Baruchi <mail.baruchi@xxxxxxxxx>
Delivery-date: Sat, 01 Dec 2007 18:35:32 -0800
Envelope-to: www-data@xxxxxxxxxxxxxxxxxx
In-reply-to: <4751A574.2040903@xxxxxxxxxx>
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>
References: <e3977d9c0712011008n1f9d9cc8x4d6aa26426d05867@xxxxxxxxxxxxxx> <4751A574.2040903@xxxxxxxxxx>
Sender: xen-users-bounces@xxxxxxxxxxxxxxxxxxx
User-agent: KMail/1.9.6 (enterprise 0.20070907.709405)
> > I noted that the lspci output are different, and I would like to know,
> > how can I make my xen virtual machine see the same Hardware, so I can
> > force a 1000 Full speed.
>
> You can't get Gigabit speed for your NIC in HVM.  Whatever network cards
> you have on the physical system, it's emulated as a 10/100 mbps Realtek
> card to the HVM.
>
> Use paravirtualized drivers for HVMs to enhance the network card
> performance and throughput, but don't expect 1000 mbps.  :-)

The virtual machine won't have hardware matching the physical system; it just 
sees whatever hardware Xen is emulating.

Xen doesn't emulate a GigE network card so you won't be able to see one in the 
guest.  However, I suspect that the 10/100mbps card will be able to transmit 
above that speed if your machine can emulate the card fast enough: because 
there's not a real hardware 100mbps ethernet card there, there actually 
shouldn't be anything limiting the speed to that.

As Sadique mentioned, if you use paravirtualised drivers in your guest (either 
by using a PV guest or by installing paravirt network drivers in an HVM 
guest) you could potentially increase the throughput and decrease the CPU 
overhead further.

Cheers,
Mark

-- 
Dave: Just a question. What use is a unicyle with no seat?  And no pedals!
Mark: To answer a question with a question: What use is a skateboard?
Dave: Skateboards have wheels.
Mark: My wheel has a wheel!

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