Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1759113AbYA3Nxf (ORCPT ); Wed, 30 Jan 2008 08:53:35 -0500 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S1756254AbYA3NxP (ORCPT ); Wed, 30 Jan 2008 08:53:15 -0500 Received: from 74-93-104-97-Washington.hfc.comcastbusiness.net ([74.93.104.97]:36407 "EHLO sunset.davemloft.net" rhost-flags-OK-FAIL-OK-OK) by vger.kernel.org with ESMTP id S1756011AbYA3NxO (ORCPT ); Wed, 30 Jan 2008 08:53:14 -0500 Date: Wed, 30 Jan 2008 05:53:33 -0800 (PST) Message-Id: <20080130.055333.192844925.davem@davemloft.net> To: ballen@gravity.phys.uwm.edu Cc: linux-kernel@vger.kernel.org, henning.fehrmann@aei.mpg.de, carsten.aulbert@aei.mpg.de, bruce.allen@aei.mpg.de, netdev@vger.kernel.org Subject: Re: e1000 full-duplex TCP performance well below wire speed From: David Miller In-Reply-To: References: X-Mailer: Mew version 5.2 on Emacs 22.1 / Mule 5.0 (SAKAKI) Mime-Version: 1.0 Content-Type: Text/Plain; charset=us-ascii Content-Transfer-Encoding: 7bit Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 730 Lines: 21 From: Bruce Allen Date: Wed, 30 Jan 2008 03:51:51 -0600 (CST) [ netdev@vger.kernel.org added to CC: list, that is where kernel networking issues are discussed. ] > (The performance of a full duplex stream should be close to 1Gb/s in > both directions.) This is not a reasonable expectation. ACKs take up space on the link in the opposite direction of the transfer. So the link usage in the opposite direction of the transfer is very far from zero. -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/