Re: TCP zero-copy

[Andrew Theurer]

On Friday 03 August 2001 04:23,  wrote:
> I believe this behaviour is only possible for cards which have the
> ability to dma what appears as a list of skb data fragments and
> also has the ability to checksum the data. Namely the Alteon, now
> 3com, ACENIC and the sun hme device.

Intel now has an e1000 driver as well.

> Does this kernel modification completely remove the need for a
> copy/checksum of the data between user and kernel space on both
> transmit and receive ?

Transmit for sure.  You should no longer see csum_partial_copy_generic() when 
using zerocopy.

> I have written a driver for an Intel ixf1002 chip, which has some
> surrounding HW, and is capable of checksumming and processing
> dma in fragments. Is there any information on what changes I
> would have to make to the driver to support zerocopy/checksum ?

Which card is this?

Andrew Theurer