Re: [net-next PATCH 0/3] net: optimize ICMP-reply code path

On Mon, 2017-01-09 at 09:43 -0800, Cong Wang wrote:

On Mon, Jan 9, 2017 at 7:03 AM, Jesper Dangaard Brouer
[off-list ref] wrote:

quoted

Use-case: The specific case I experienced this being a bottleneck is,
sending UDP packets to a port with no listener, which obviously result
in kernel replying with ICMP Destination Unreachable (type:3), Port
Unreachable (code:3), which cause the bottleneck.

Why this is a case we should care about for performance?

This is called provisioning.

If you have a server farm that was qualified to handle 100 Mpps,
you want to absorb these 100 Mpps, even if the UDP server is restarted
in a clean or catastrophic mode.

The catastrophic mode would be the case that Jesper described : No UDP
socket is bound and ready to receive packets.