Re: [Qemu-devel] Ideas wiki for GSoC 2010

[Muli Ben-Yehuda <muli@il.ibm.com>]

On Mon, Mar 15, 2010 at 02:03:11PM +0100, Joerg Roedel wrote:

> On Mon, Mar 15, 2010 at 05:53:13AM -0700, Muli Ben-Yehuda wrote:

> > On Mon, Mar 15, 2010 at 02:25:41PM +0200, Avi Kivity wrote:

> > > On 03/10/2010 11:30 PM, Luiz Capitulino wrote:
> > 
> > > >  Hi there,
> > > >
> > > >  Our wiki page for the Summer of Code 2010 is doing quite well:
> > > >
> > > >http://wiki.qemu.org/Google_Summer_of_Code_2010
> > > 
> > > I will add another project - iommu emulation.  Could be very
> > > useful for doing device assignment to nested guests, which could
> > > make testing a lot easier.
> > 
> > Our experiments show that nested device assignment is pretty much
> > required for I/O performance in nested scenarios.
> 
> Really? I did a small test with virtio-blk in a nested guest (disk
> read with dd, so not a real benchmark) and got a reasonable
> read-performance of around 25MB/s from the disk in the l2-guest.

Netperf running in L1 with direct access: ~950 Mbps throughput with
25% CPU utilization. Netperf running in L2 with virtio between L2 and
L1 and direct assignment between L1 and L0: roughly the same
throughput, but over 90% CPU utilization! Now extrapolate to 10GbE.

Cheers,
Muli