Re: [libvirt] [PATCH] kvm/virtio: Set IFF_VNET_HDR when setting up tap fds
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. Its going to need todo this anyway for the
scenario where QEMU allocates the TAP fd, so it might as well
enable it for pre-allocated TAP fds passed in from external
apps.
Daniel
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