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Re: [Xen-users] NIC Offloading Confusion

To: Xen List <xen-users@xxxxxxxxxxxxxxxxxxx>
Subject: Re: [Xen-users] NIC Offloading Confusion
From: "Fajar A. Nugraha" <fajar@xxxxxxxxx>
Date: Fri, 24 Apr 2009 19:21:51 +0700
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On Fri, Apr 24, 2009 at 5:41 PM, Robert Dunkley <Robert@xxxxxxxxx> wrote:
> I have been using the built in Xen Paravirt NIC drivers for paravirt
> networking and had bad performance until I disabled all offload setting
> on the bridge and paravirt nic (From Dom0).

Are they PV guests, or HVM guests with PV drivers?

> There are 2 related questions I have, where should I be tweaking the
> offload settings, the Dom0 Physical NIC, The Bridge or the DomU NIC?
> Which settings in particular tend to cause trouble? (I just disabled all
> of them because this was a server that is in use that I converted to
> paravirt dirvers)

I'd start with tx and LSO on domU.

> Does anyone have any Ethtool -K recommendations for a Xen,
> Redhat/Centos, Intel PCI-Express and Intel Legacy PCI drivers?

It should be "None".
If you're using RHEL and you still have to disable some offload, then
you should file a bug to Redhat :)

That being said, I'm using RHEL5.3 with Broadcom (tg3 and bnx2) NICs
mostly, and they're working correctly without any need for offload
setting change. If you're still using old version, updating with yum
might help.



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