Messages in this thread | | | From | "Xin, Xiaohui" <> | Date | Thu, 11 Feb 2010 15:40:08 +0800 | Subject | RE: [PATCH 0/3] Provide a zero-copy method on KVM virtio-net. |
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>>On Wednesday 10 February 2010, Xin Xiaohui wrote: > >The idea is simple, just to pin the guest VM user space and then > >let host NIC driver has the chance to directly DMA to it. > >The patches are based on vhost-net backend driver. We add a device > >which provides proto_ops as sendmsg/recvmsg to vhost-net to > >send/recv directly to/from the NIC driver. KVM guest who use the > >vhost-net backend may bind any ethX interface in the host side to > >get copyless data transfer thru guest virtio-net frontend. >> >> We provide multiple submits and asynchronous notifiicaton to > >vhost-net too.
>This does a lot of things that I had planned for macvtap. It's >great to hear that you have made this much progress. > >However, I'd hope that we could combine this with the macvtap driver, >which would give us zero-copy transfer capability both with and >without vhost, as well as (tx at least) when using multiple guests >on a macvlan setup.
You mean the zero-copy can work with macvtap driver without vhost. May you give me some detailed info about your macvtap driver and the relationship between vhost and macvtap to make me have a clear picture then?
>For transmit, it should be fairly straightforward to hook up >your zero-copy method and the vhost-net interface into the >macvtap driver. > >You have simplified the receiv path significantly by assuming >that the entire netdev can receive into a single guest, right?
Yes.
>I'm assuming that the idea is to allow VMDq adapters to simply >show up as separate adapters and have the driver handle this >in a hardware specific way.
Does the VMDq driver do so now?
>My plan for this was to instead move support for VMDq into the >macvlan driver so we can transparently use VMDq on hardware where >available, including zero-copy receives, but fall back to software >operation on non-VMDq hardware.
Arnd
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