[Date Prev][Date Next]   [Thread Prev][Thread Next]   [Thread Index] [Date Index] [Author Index]

Re: [libvirt] [PATCH] kvm/virtio: Set IFF_VNET_HDR when setting up tap fds



On Wed, Aug 13, 2008 at 04:14:10PM +0100, Mark McLoughlin wrote:
> On Wed, 2008-08-13 at 16:01 +0100, Daniel P. Berrange wrote:
> > On Wed, Aug 13, 2008 at 03:53:27PM +0100, Mark McLoughlin wrote:
> > > By enabling this flag on the tap fds we create, we greatly increase
> > > the achievable throughput with virtio_net.
> > > 
> > > However, we need to be careful to only set the flag when a) KVM has
> > > support for this ABI and b) the value of the flag is queryable using
> > > the TUNGETIFF ioctl.
> > 
> > This suggests to me that QEMU should be a the one enabling this
> > flag, not libvirt.
> 
> It has to be done before adding it to the bridge and can't be changed
> afterwards.

Urgh, that's not nice :-(

> (Which perhaps suggests the kernel API is a little dumb, but ...)

<expletive deleted>  

If we have todo this in libvirt, then the patch looks like a reasonable
way todo it, but be nice if it wasn't our responsibility

Daniel
-- 
|: Red Hat, Engineering, London   -o-   http://people.redhat.com/berrange/ :|
|: http://libvirt.org  -o-  http://virt-manager.org  -o-  http://ovirt.org :|
|: http://autobuild.org       -o-         http://search.cpan.org/~danberr/ :|
|: GnuPG: 7D3B9505  -o-  F3C9 553F A1DA 4AC2 5648 23C1 B3DF F742 7D3B 9505 :|


[Date Prev][Date Next]   [Thread Prev][Thread Next]   [Thread Index] [Date Index] [Author Index]