[FreeBSD 8.2 amd64 XENHVM] DomU terrible network performance trought NAT

[Justin T. Gibbs]

On 5/12/11 11:48 AM, Janne Snabb wrote:
> On Thu, 12 May 2011, Laurent Cligny wrote:
>
>> All FreeBSD VM are 8.2 amd64 with XENHVM kernel anf the Linux VM is a
>> Paravirtualized Debian amd64.
> My suggestion would be to try out the same setup with GENERIC kernel
> and the rtl driver (or even better e1000 if your Xen allows it)
> which is easy to do to make a simple comparison.
>
> In one of my recent benchmarks the FreeBSD Xen PV network driver
> performed very well in one direction, but very badly in the other.
> Using rtl or e1000 gave much better TCP throughput if you care
> equally about both directions. This benchmark was done only for
> internal TCP traffic between a Linux dom0 and FreeBSD dumU, the
> traffic never entered a real NIC.

Do you recall which path was slow (rx or tx from the perspective of
the FreeBSD driver) and what the relative difference in performance
was between the two approaches?

--
Justin