From mboxrd@z Thu Jan 1 00:00:00 1970 From: Breno Leitao Subject: e1000 performance issue in 4 simultaneous links Date: Thu, 10 Jan 2008 14:17:19 -0200 Message-ID: <1199981839.8931.35.camel@cafe> Mime-Version: 1.0 Content-Type: text/plain Content-Transfer-Encoding: 7bit To: netdev@vger.kernel.org Return-path: Received: from igw2.br.ibm.com ([32.104.18.25]:38120 "EHLO igw2.br.ibm.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1755499AbYAJQRZ (ORCPT ); Thu, 10 Jan 2008 11:17:25 -0500 Received: from mailhub1.br.ibm.com (mailhub1 [9.18.232.109]) by igw2.br.ibm.com (Postfix) with ESMTP id 5ABE817F433 for ; Thu, 10 Jan 2008 14:11:42 -0200 (BRDT) Received: from d24av02.br.ibm.com (d24av02.br.ibm.com [9.18.232.47]) by mailhub1.br.ibm.com (8.13.8/8.13.8/NCO v8.7) with ESMTP id m0AGHLbG3756118 for ; Thu, 10 Jan 2008 14:17:22 -0200 Received: from d24av02.br.ibm.com (loopback [127.0.0.1]) by d24av02.br.ibm.com (8.12.11.20060308/8.13.3) with ESMTP id m0AGHLuX028318 for ; Thu, 10 Jan 2008 14:17:21 -0200 Received: from [9.18.250.201] (cafe.br.ibm.com [9.18.250.201]) by d24av02.br.ibm.com (8.12.11.20060308/8.12.11) with ESMTP id m0AGHJE4028248 for ; Thu, 10 Jan 2008 14:17:20 -0200 Sender: netdev-owner@vger.kernel.org List-ID: Hello, I've perceived that there is a performance issue when running netperf against 4 e1000 links connected end-to-end to another machine with 4 e1000 interfaces. I have 2 4-port interfaces on my machine, but the test is just considering 2 port for each interfaces card. When I run netperf in just one interface, I get 940.95 * 10^6 bits/sec of transfer rate. If I run 4 netperf against 4 different interfaces, I get around 720 * 10^6 bits/sec. If I run the same test against 2 interfaces I get a 940 * 10^6 bits/sec transfer rate also, and if I run it against 3 interfaces I get around 850 * 10^6 bits/sec performance. I got this results using the upstream netdev-2.6 branch kernel plus David Miller's 7 NAPI patches set[1]. In the kernel 2.6.23.12 the result is a bit worse, and the the transfer rate was around 600 * 10^6 bits/sec. [1] http://marc.info/?l=linux-netdev&m=119977075917488&w=2 PS: I am not using a switch in the middle of interfaces (they are end-to-end) and the connections are independents. -- Breno Leitao