[Date Prev][Date Next][Thread Prev][Thread Next][Date Index][Thread Index]

Re: [Xen-users] PCI passthrough, poor network performance in upload direction


  • To: "Luis F Urrea" <lfurrea@xxxxxxxxx>
  • From: "Todd Deshane" <deshantm@xxxxxxxxx>
  • Date: Thu, 11 Dec 2008 16:20:07 -0500
  • Cc: xen-users@xxxxxxxxxxxxxxxxxxx
  • Delivery-date: Thu, 11 Dec 2008 13:21:58 -0800
  • Domainkey-signature: a=rsa-sha1; c=nofws; d=gmail.com; s=gamma; h=message-id:date:from:reply-to:to:subject:cc:in-reply-to :mime-version:content-type:content-transfer-encoding :content-disposition:references; b=dqC4JVKpQyYyAuvLnBcgEtr4eLWKtXSPNh4br2+2IP+psYt9OWIXHnkZCHwBlP7/dF C7lX8oZFuSU16UEdxLd4fvZ91me+rWxstHe0ZmCAPgBTU7DPFkUqfvDqalk3zz4ESND3 ookRA2VLm37P7S8h5DFXeTKOBYEFRkXyMRF2g=
  • List-id: Xen user discussion <xen-users.lists.xensource.com>

On Thu, Dec 11, 2008 at 4:10 PM, Luis F Urrea <lfurrea@xxxxxxxxx> wrote:
> Hi all,
>
> I have been having an issue for over a year with several Xen installations
> and have not been able to find out if this is just something I am missing.
>
> Basically I am trying to configure a firewall with two ethernet cards in a
> domU using pci passthrough. I am hiding the Ethernet cards at boot time via
> the pciback.hide kernel option.
>
> Right now I am running Xen 3.3.0 and the two Ethernet cards are passed to
> the FW domU.
>
> The FW domU is not configured with a vif interface to the bridge, so
> basically communication with DomO passes through the external hardware.
>
> Tests using iperf show me that download bandwidth from the FW domU to an
> external machine connected to the switch go as high as 94 Mbits/sec. However
> upload bandwidth from a laptop to the domU give me a maximum of 574
> Kbits/sec which basically is not enough to cover the upload bw of some
> internet connections.
>
> I have read recommendations about using ethtool -K ethX tx off in dom U, but
> in this case the tx ring does not seem the be the issue since the download
> speeds are just fine. Using 'ethtool -K rx eth0 off' did not show any
> improvements.
>
> Since the guest domain has exclusive access to both Ethernet cards I suppose
> that the overhead is introduced somewhere in the domU's kernel but I
> wouldn't exactly know where else to look for a possible fix.
>
> Your input is appreciated.
>

What is your guest kernel?

Is this all PV?

What is your hardware (both NIC and system)?

What driver is the guest using for the device?

Cheers,
Todd

-- 
Todd Deshane
http://todddeshane.net
http://runningxen.com

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


 


Rackspace

Lists.xenproject.org is hosted with RackSpace, monitoring our
servers 24x7x365 and backed by RackSpace's Fanatical Support®.