From mboxrd@z Thu Jan 1 00:00:00 1970 From: Jeff Kirsher Subject: Re: 3.4.1 and 3.5-rc1 Packet lost at 250Mb/s Date: Tue, 09 Oct 2012 21:59:27 -0700 Message-ID: <507500AF.4080209@gmail.com> References: <409ac8b30a6994028562e1a159ac60aa@justnet.pl> <1349677373.21172.2756.camel@edumazet-glaptop> <9819d6943a7cfddfc8fa49217aa4842e@justnet.pl> <1349689640.21172.3008.camel@edumazet-glaptop> <80bb011e8f1289218087633fd7b115ea@justnet.pl> <5072C063.6000302@tomt.net> <1349698406.21172.3168.camel@edumazet-glaptop> <5072C7F4.1090002@tomt.net> <5072CE29.5010504@tomt.net> Reply-To: jeffrey.t.kirsher@intel.com Mime-Version: 1.0 Content-Type: text/plain; charset=UTF-8; format=flowed Content-Transfer-Encoding: QUOTED-PRINTABLE Cc: Andre Tomt , Eric Dumazet , Netdev , Jesse Brandeburg To: adam.niescierowicz@justnet.pl Return-path: Received: from mga03.intel.com ([143.182.124.21]:65013 "EHLO mga03.intel.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1752185Ab2JJE7b (ORCPT ); Wed, 10 Oct 2012 00:59:31 -0400 In-Reply-To: Sender: netdev-owner@vger.kernel.org List-ID: On 10/09/2012 12:56 PM, Nie=C5=9Bcierowicz Adam wrote: > W dniu 08.10.2012 14:59, Andre Tomt napisa=C5=82(a): > >> On 08. okt. 2012 14:32, Andre Tomt wrote: >> >>> On 08. okt. 2012 14:13, Eric Dumazet wrote: >>> >>>> On Mon, 2012-10-08 at 14:00 +0200, Andre Tomt wrote: >>>> >>>>> On 08. okt. 2012 12:49, Nie=C5=9Bcierowicz Adam wrote: >>>>> >>>>>> W dniu 08.10.2012 11:47, Eric Dumazet napisa=C5=82(a): >>>>>> >>>>>>> Anyway you dont say where are drops, (ifconfig give us very few >>>>>>> drops) >>>>>> you can see no losses(drop), but a temporary decline in traffic >>>>>> on the interface to 0kb/s >>>>> This sounds very familiar, could it be something similar to: >>>>> http://marc.info/?l=3Dlinux-netdev&m=3D134594936016796&w=3D3 [1] = The chip >>>>> seems to be of the same family (though not model) >>>> Yes, but Adam says 3.4.1 already has a problem, while commit >>>> 2cb7a9cc008c25dc03314de563c00c107b3e5432 is in 3.5 only. Since Ada= m >>>> uses Intel e1000e, it could be the BQL related problem. >>> The other chips have had DMA burst flag enabled for longer, so that= he >>> sees the same problem in 3.4 while I'm not makes sense. Hmm, as 3.4= is >>> when BQL went in (IIRC) it seems very likely that this BQL issue is= the >>> problem for both of us. >> >> To clarify; I think the DMA burst flag in the driver triggers the BQ= L >> related issue. Judging by the patchwork link for wthresh=3D1 this se= ems >> very related indeed. >> >> Removing the FLAG2_DMA_BURST flag for 82574 in the driver works for = me. >> Adam, it might be worth testing out a build on your system too with = the >> flag removed. If you try the attached patch (for 3.6, probably OK fo= r >> 3.5) and the problem dissapears, we are probably at least talking ab= out >> the same bug. > > after applying the patch everything looks good, no visible loss > > Do you expect to correct the bug in mainline?=20 Jesse Brandenburg is working on a patch for upstream currently to fix=20 the issue.