On Wed, 2013-10-30 at 12:19 +0800, Herbert Xu wrote:

On Tue, Oct 29, 2013 at 09:16:17PM -0700, Eric Dumazet wrote:

quoted

The thing is this only matters for hosts receiving at line rate on few
TCP flows.

A router should not build too big GRO packets, as it adds latencies.

Really, we had to make TSO packets being auto sized, lets not add the
syndrome again.

So I do not really understand David concern about emitting a warning.

If a machine is used as a router, building GRO packets of 17 MSS is
absolutely fine.

It's not just routers you know, we use the same code on bridges
as part of virtualisation.  So it absolutely does matter.

What matters ?

GRO ?

Or making size of GRO packets not too big, or making them bigger ?

Before my patch, GRO packets were 17 MSS, and nobody complained packets
were too small, so what are you saying exactly ?