[fedora-virt] Poor performace for e1000 and other fully virtualized netcard

[Ján ONDREJ (SAL)]

On Fri, Sep 06, 2013 at 01:06:04AM +0530, Amit Shah wrote:
> On (Thu) 05 Sep 2013 [21:21:00], Ján ONDREJ (SAL) wrote:
> > On Fri, Sep 06, 2013 at 12:22:45AM +0530, Amit Shah wrote:
> > > On (Thu) 05 Sep 2013 [15:26:52], Ján ONDREJ (SAL) wrote:
> > > 
> > > > As described in other bug, virtio net driver has time skew problems, so
> > > > I can't use it. :-(
> > > 
> > > Please share details -- link to bug report or mail list post.
> > 
> > Thread 2 month ago here:
> > 
> >   https://lists.fedoraproject.org/pipermail/virt/2013-July/003714.html
> > 
> > or rhbz:
> > 
> >   https://bugzilla.redhat.com/show_bug.cgi?id=982459
> > 
> > Btw, latest 3.9 kernel for fc18 works well:
> >   kernel-3.9.11-200.fc18.x86_64  -  fast network speed
> 
> That thread and bug says you have problems with virtio and Windows
> guests.  You're here saying the kernel version matters.  Does this
> mean that the host kernel version matters for you when you use e1000
> or virtio-net cards with Windows guests?

Time skew problems are not kernel specific, this bug is prensent always.
But this happens only if virtio-net windows driver is installed in guest.

Slow network for e1000 and possibly other network cards is kernel specific.
Kernels 3.10+ on hosts.

Btw, another bug in 3.9.11. One guest stopped to communicate on
ethernet. When trying to restart it, shutdown completed, but qemu process is
still running in "D" (dead) state on host. Unable to kill it. :-(

Which Fedora kernel should be fully functional? :-)

At our university we are using Fedora host over years, using mostly linux
guests, but also some windows. My problems started with 3.10 kernels.
I don't remember, which 3.9 kernel I used before.

					SAL