From mboxrd@z Thu Jan 1 00:00:00 1970 From: alekcejk@googlemail.com Subject: Re: Re: limited network bandwidth with 3.2.x kernels Date: Thu, 16 Feb 2012 19:54:54 +0200 Message-ID: <1461927.R8CTCUdqT9@localhost.localdomain> References: <1329399616.9395.9.camel@edumazet-HP-Compaq-6005-Pro-SFF-PC> <20120216.120149.437368615973561397.davem@davemloft.net> Mime-Version: 1.0 Content-Type: text/plain; charset=koi8-r Content-Transfer-Encoding: QUOTED-PRINTABLE To: Neal Cardwell , netdev@vger.kernel.org Return-path: Received: from mail-bk0-f46.google.com ([209.85.214.46]:49914 "EHLO mail-bk0-f46.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1753944Ab2BPSDb convert rfc822-to-8bit (ORCPT ); Thu, 16 Feb 2012 13:03:31 -0500 Received: by bkcjm19 with SMTP id jm19so2231195bkc.19 for ; Thu, 16 Feb 2012 10:03:30 -0800 (PST) In-Reply-To: Sender: netdev-owner@vger.kernel.org List-ID: =F7 =D3=CF=CF=C2=DD=C5=CE=C9=C9 =CF=D4 =FE=C5=D4=D7=C5=D2=C7 16 =C6=C5=D7= =D2=C1=CC=D1 2012 12:22:29 =D7=D9 =CE=C1=D0=C9=D3=C1=CC=C9: > Our team has also run into issues with GRO/LRO "stretch ACKs", and > their negative impact on TCP performance. We have a patch that we've > been working with that deals with the sender-side issues. It turns ou= t > that neither the ABC nor non-ABC byte counting quite fixes the stretc= h > ACKs issues. >=20 > On the receiver side, the approach of changing tcp_grow_window() and > __tcp_grow_window() to adjust things in terms of actual packet size > rather than a fixed 2*MSS sounds great to me as well. >=20 > In terms of the original 3.1 vs 3.2 issue report that started this > thread, I didn't see any evidence of LRO or GRO causing stretch ACKs. > (Alexey, would you be able to confim by running "ethtool -k eth0" on > both kernels?) So it seems that probably the original issue is > unrelated to stretch ACKs? >=20 > neal Looks like "ethtool -k eth0" shows the same with both kernels: Offload parameters for eth0: rx-checksumming: on tx-checksumming: on scatter-gather: on tcp-segmentation-offload: off udp-fragmentation-offload: off generic-segmentation-offload: on generic-receive-offload: on large-receive-offload: off rx-vlan-offload: off tx-vlan-offload: off ntuple-filters: off receive-hashing: off