Re: [kvm-devel] QEMU PIC indirection patch for in-kernel APIC work

Avi Kivity
2007-04-05T07:17:40Z

Rusty Russell wrote:
> You didn't quote Anthony's point about "it's more about there not being
> good enough userspace interfaces to do network IO."
>
> It's easier to write a kernel-space network driver, but it's not
> obviously the right thing to do until we can show that an efficient
> packet-level userspace interface isn't possible. I don't think that's
> been done, and it would be interesting to try.
>

In the case of networking, the copyful interfaces on receive are driven
by the hardware not knowing how to split the header from the data. On
transmit I agree, it could be made copyless from userspace (somthing
like sendfilev, only not file oriented).

--
Do not meddle in the internals of kernels, for they are subtle and quick to panic.