From mboxrd@z Thu Jan 1 00:00:00 1970 From: David Miller Subject: Re: tcp bw in 2.6 Date: Tue, 02 Oct 2007 13:33:22 -0700 (PDT) Message-ID: <20071002.133322.52193802.davem@davemloft.net> References: <20071002150935.GC17418@bitmover.com> Mime-Version: 1.0 Content-Type: Text/Plain; charset=us-ascii Content-Transfer-Encoding: 7bit Cc: lm@bitmover.com, herbert@gondor.apana.org.au, wscott@bitmover.com, netdev@vger.kernel.org To: torvalds@linux-foundation.org Return-path: Received: from 74-93-104-97-Washington.hfc.comcastbusiness.net ([74.93.104.97]:44452 "EHLO sunset.davemloft.net" rhost-flags-OK-FAIL-OK-OK) by vger.kernel.org with ESMTP id S1753498AbXJBUdW (ORCPT ); Tue, 2 Oct 2007 16:33:22 -0400 In-Reply-To: Sender: netdev-owner@vger.kernel.org List-Id: netdev.vger.kernel.org From: Linus Torvalds Date: Tue, 2 Oct 2007 12:27:53 -0700 (PDT) > We see a single packet containing 16060 bytes, which seems to be because > of TSO on the sending side (you did your tcpdump on the sender, no?), so > it will actually be broken up into 11 1460-byte regular frames by the > network card, since they started out agreeing on a standard 1460-byte MSS. > So the above is not a jumbo frame, it just kind of looks like one when you > capture it on the sender side. > > And maybe a 32kB window is not big enough when it causes the networking > code to basically just have a single packet outstanding. We fixed a lot of bugs in TSO last year. It would be really great to see numbers with a more recent kernel than 2.6.18