Re: Large performance regression with 6in4 tunnel (sit)

Hi Stephen,

On 2016/11/25 10:45, Stephen Rothwell wrote:

Hi Eli,

On Fri, 25 Nov 2016 10:18:12 +0800 Eli Cooper [off-list ref] wrote:

quoted

Sounds like TSO/GSO packets are not properly segmented and therefore
dropped.

Could you first try turning off segmentation offloading for the tunnel
interface?
    ethtool -K sit0 tso off gso off

On Thu, 24 Nov 2016 18:30:14 -0800 Eric Dumazet [off-list ref]

quoted

You also could try to disable TSO and see if this makes a difference

ethtool -K sixtofour0 tso off

So turning off tso brings performance up to IPv4 levels ...

Thanks for that, it solves my immediate problem.

I think this is similar to the bug I fixed in commit ae148b085876
("ip6_tunnel: Update skb->protocol to ETH_P_IPV6 in ip6_tnl_xmit()").

I can reproduce a similar problem by applying xfrm to sit traffic.
TSO/GSO packets are dropped when IPSec is enabled, and IPv6 throughput
drops to 10s of Kbps. I am not sure if this is the same issue you
experienced, but I wrote a patch that fixed at least the issue I had.

Could you test the patch I sent to the mailing list just now?

Thanks,
Eli