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SubjectRe: [PATCH 0/16 v6] PCI: Linux kernel SR-IOV support
On Thu, Nov 06, 2008 at 04:40:21PM -0600, Anthony Liguori wrote:

> We've been talking about avoiding hardware passthrough entirely and
> just backing a virtio-net backend driver by a dedicated VF in the
> host. That avoids a huge amount of guest-facing complexity, let's
> migration Just Work, and should give the same level of performance.

I don't believe that it will, and every benchmark I've seen or have
done so far shows a significant performance gap between virtio and
direct assignment, even on 1G ethernet. I am willing however to
reserve judgement until someone implements your suggestion and
actually measures it, preferably on 10G ethernet.

No doubt device assignment---and SR-IOV in particular---are complex,
but I hardly think ignoring it as you seem to propose is the right
approach.

Cheers,
Muli
--
The First Workshop on I/O Virtualization (WIOV '08)
Dec 2008, San Diego, CA, http://www.usenix.org/wiov08/
<->
SYSTOR 2009---The Israeli Experimental Systems Conference
http://www.haifa.il.ibm.com/conferences/systor2009/


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