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Re: [Xen-devel] [0/5] [NET]: Add TSO support

On Tue, Jun 27, 2006 at 02:27:20PM +0100, Keir Fraser wrote:
> Do you have any numbers for transmit to external host? It'd be 
> particularly interesting to see how you improve CPU overheads of 
> domain0 and domainU (since throughput isn't usually much less than 
> native anyway, but CPU overhead can be significantly higher).

Sure.  Here are figures from xm top on the same laptop.  It only has
an e100 so there would be a lot more savings with a TSO-capable NIC:

                        dom0            domU
idle:                   3.2%            0%
TSO:                    17.7%           5.9%
baseline:               18.6%           6.9%

So overall it's 22.3% vs. 20.4%.  In both cases the actual throughput
is around 92Mb/s.

BTW, the difference here is much smaller than inter-domain traffic
because this is purely send-only while with inter-domain traffic we
actually have the corresponding benefit of the receive side as well
with the super-packet passing through the receive side as is.

> Comments on the patches:

I will repost tomorrow with your comments taken into consideration.

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