Re: [PATCH] Request for comments on ixgbe TSO support

[Stephen Hemminger <stephen-OTpzqLSitTUnbdJkjeBofR2eb7JE58TQ@public.gmane.org>]

On Fri, 4 Oct 2013 22:10:33 +0300
jigsaw <jigsaw-Re5JQEeQqe8AvxtiuMwx3w@public.gmane.org> wrote:

> Hi Stephen,
> 
> Thanks for showing a bigger picture.
> 
> GSO is quite big implementation, that I think it won't be easily
> ported to DPDK. The mbuf needs to be equipped with many fields from
> skb to be able to deal with GSO.
> Do you have the plan to port GSO to DPDK, or you would like to keep
> GSO in scope of virtio?
> 
> Regarding checksum flags, actually I was also thinking of extending
> ol_flags but then I gave it up coz I was worried about the size of
> mbuf.
> My current patch has to push some work to user, due to the fact that
> mbuf delivers too few info (such as L2 and L3 protocol details).
> 
> Besides, as you mentioned, the ixgbe driver doesn't leverage the
> hardware receive checksum offloading at all. And if this is to be
> supported, the checksum flag need further extension.
> (On the other hand, TSO doesn't care about receive checksum offloading).
> Again, do you have plans to extend cksum flags so that virio feels
> more comfortable with DPDK?
> 
> Hi Venky,
> 
> I can either make the commit now as is, or wait till the cksum flags
> extension is in place. If Stephen (or somebody else) has the plan for
> better support for cksum offloading or GSO, it is perhaps better to
> implement TSO on top of that.
> 
> BTW, I have another small question. Current TSO patch offloads the
> TCP/IP pseudo cksum work to user. Do you think DPDK could provide some
> utility functions for TCP/IPv4/IPv6 pseudo cksum calculation and
> updating?
> 
> thx &
> rgds,
> -Qinglai

I want to get Tx checksum offload in virtio working first.
Just looking ahead to Rx.