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

lists.openwall.net		lists / announce owl-users owl-dev john-users john-dev passwdqc-users yescrypt popa3d-users / oss-security kernel-hardening musl sabotage tlsify passwords / crypt-dev xvendor / Bugtraq Full-Disclosure linux-kernel linux-netdev linux-ext4 linux-hardening linux-cve-announce PHC
Open Source and information security mailing list archives

Hash Suite: Windows password security audit tool. GUI, reports in PDF.

[<prev] [next>] [<thread-prev] [thread-next>] [day] [month] [year] [list]

Message-ID: <a4a7b888-04d1-55ce-28de-cc15f01a15fc@gmx.com>
Date:   Fri, 25 Nov 2016 14:05:04 +0800
From:   Eli Cooper <elicooper@....com>
To:     Stephen Rothwell <sfr@...b.auug.org.au>
Cc:     netdev@...r.kernel.org
Subject: 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 <elicooper@....com> wrote:
>> 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 <eric.dumazet@...il.com>
>> 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