From mboxrd@z Thu Jan 1 00:00:00 1970 From: Rick Jones Subject: Re: PROBLEM: Bnx2x Checksum/Length Error Over GRE Tunnel Date: Tue, 03 Feb 2015 11:29:28 -0800 Message-ID: <54D12198.1000507@hp.com> References: <54D0A345.2030108@skyatlas.com> <54D10DFE.1070604@skyatlas.com> <1422989196.907.34.camel@edumazet-glaptop2.roam.corp.google.com> Mime-Version: 1.0 Content-Type: text/plain; charset=utf-8; format=flowed Content-Transfer-Encoding: QUOTED-PRINTABLE Cc: Network Development To: Eric Dumazet , =?UTF-8?B?RXJlbiBUw7xya2F5?= Return-path: Received: from g9t1613g.houston.hp.com ([15.240.0.71]:60363 "EHLO g9t1613g.houston.hp.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S966159AbbBCT3g (ORCPT ); Tue, 3 Feb 2015 14:29:36 -0500 In-Reply-To: <1422989196.907.34.camel@edumazet-glaptop2.roam.corp.google.com> Sender: netdev-owner@vger.kernel.org List-ID: On 02/03/2015 10:46 AM, Eric Dumazet wrote: > On Tue, 2015-02-03 at 20:05 +0200, Eren T=C3=BCrkay wrote: >> Hello, >> >> I am having incorrect checksum and length calculation error when usi= ng >> GRE tunnel and this leads to unstable/unreliable connections where e= ven >> simple nc connection cannot be made correctly due to a lot of TCP >> retransmissions. The reported iperf output becomes 23Kbit/s. >> >> When I disable tx checksumming with "ethtool -K eth0 tx off", the >> problem seems to be solved but then I lose tcp segmentation offloadi= ng >> support, without which adds an additional overhead on 10Gbit network >> interface. With tx off, I get 4 to 7Gbit/s with parallel 40 connecti= ons >> using iperf. >> >> In tcpdump output (tcpdump -i em1 proto gre) when tx checksumming is >> enabled, I see "checksum error" in every packet + "IP truncated-ip - >> 63631 bytes missing!" messages, and a lot of TCP >> retransmissions. When tx is off, checksums are correct but I get 4-7= Gbit >> output. With GSO generalization code in [0] it is reported that >> 9.3Gbit/s is possible over GRE tunnel but I'm nowhere near these res= ults. > > Strange, I am using bnx2x with no such problem. A pedantic question, but do the driver and firmware versions match=20 between your setup and his? rick