Re: [PATCH 0/9][RFC] KVM virtio_net performance

Rusty Russell
2008-07-27T06:49:12Z

On Saturday 26 July 2008 19:45:36 Avi Kivity wrote:
> > 5) Eliminating an extra copy on the host->guest path only makes a
> > barely measurable difference.
>
> That's expected on a host->guest test. Zero copy is mostly important
> for guest->external, and with zerocopy already enabled in the guest
> (sendfile or nfs server workloads).

Note that this will also need the copyless tun patches. If we're doing one
copy from userspace->kernel anyway, this extra copy is probably lost in the
noise.

Cheers,
Rusty.