Re: [PATCH net-next,RFC 00/13] New fast forwarding path

On Thu, Jun 14, 2018 at 4:58 PM, David Miller [off-list ref] wrote:

From: Tom Herbert <redacted>
Date: Thu, 14 Jun 2018 13:52:03 -0700

quoted

IIRC, there was a similar proposal a while back that want to bundle
packets of the same flow together (without doing GRO) so that they
could be processed by various functions by looking at just one
representative packet in the group. The concept had some promise, but
in the end it created quite a bit of complexity since at some point
the packet bundle needed to be undone to go back to processing the
individual packets.

You're probably talking about Edward Cree's SKB list stuff, and as
per his presenation at netconf 2 weeks ago he plans to revitalize
it given how Spectre et al. gives cause to reevaluate all bulking
techniques.nearly

The use case for that will be an interesting question. GSO/GRO solves
the problem for TCP and this extends to nearly all cases where TCP is
in an encapsulated packet. Super efficient forwarding can be done in
XDP/BPF (without needing overhead of GSO/GRO). That pretty much leaves
UDP as non-encapsulation end protocol, which I guess these days pretty
much means QUIC :-) I am still interested to see if we can implement
GSO/GRO for QUIC (via a generic GSO/GRO BPF function so we don't
hardcode any QUIC protocol or other application protocols in kernel).

Tom