Re: linux-3.0.18+r8169+ipv4/tcp forwarding = tso/gso weirdness and performance degration

On Wed, 14 Mar 2012 19:29:14 +0000 Ben Hutchings
[off-list ref] wrote:

On Wed, 2012-03-14 at 19:29 +0200, Timo Teras wrote:
[...]

quoted

gro off. I am even trying now with:

Offload parameters for eth2:
rx-checksumming: off
tx-checksumming: off
scatter-gather: off
tcp segmentation offload: off
udp fragmentation offload: off
generic segmentation offload: off

[...]

GRO isn't even reported there!  Apparently you need a newer version of
ethtool.

Very good point. I thought gso also enabled gro, but seems that my
ethtool was old.

And GRO was enabled along with some other stuff. Turning GRO off made
my tcp performance immediately a lot better; jumped from 2MB/s to 8MB/s
or so (not ideal yet, though; but the remainder of the difference could
be related to other issue).

So something is definitely broke in 3.0.x with GRO enabled, but GSO off.