Re: RFC: softint-based if_input

[Thor Lancelot Simon <tls%panix.com@localhost>]

On Mon, Jan 25, 2016 at 03:52:08PM -0600, David Young wrote:
> 
> That stopped the user-tickle watchdog from firing.  It was handy having
> a full-fledged thread context to process packets in.  But there were
> trade-offs.  As Matt Thomas pointed out to me, if it takes longer for
> the NIC to read the next packet off of the network than it takes your
> thread to process the current packet, then your Rx thread is going to go
> back to sleep again after every single packet.  So there's potentially
> a lot of context-switch overhead and latency when you're receiving
> back-to-back large packets.

Linux passes more than one packet at a time between protocol layers
(either with hardware assist from NICs that do "large receive offload"
or faked up early in the processing path elsewise.  Would that help?

Thor