Re: [Intel IOMMU 00/10] Intel IOMMU support, take #2

["Keshavamurthy, Anil S" <anil.s.keshavamurthy@intel.com>]

On Tue, Jun 26, 2007 at 11:11:25AM -0400, Muli Ben-Yehuda wrote:
> On Tue, Jun 26, 2007 at 08:03:59AM -0700, Arjan van de Ven wrote:
> > Muli Ben-Yehuda wrote:
> > >How much? we have numbers (to be presented at OLS later this week)
> > >that show that on bare-metal an IOMMU can cost as much as 15%-30% more
> > >CPU utilization for an IO intensive workload (netperf). It will be
> > >interesting to see comparable numbers for VT-d.
> > 
> > for VT-d it is a LOT less. I'll let anil give you his data :)
> 
> Looking forward to it. Note that this is on a large SMP machine with
> Gigabit ethernet, with netperf TCP stream. Comparing numbers for other
> benchmarks on other machines is ... less than useful, but the numbers
> themeselves are interesting.
Our initial benchmark results showed we had around 3% extra CPU 
utilization overhead when compared to native(i.e without IOMMU).
Again, our benchmark was on small SMP machine and we used
iperf and a 1G ethernet cards.

Going forward we will do more benchmark tests and will share the
results.

-Anil