From mboxrd@z Thu Jan 1 00:00:00 1970 From: Ben Hutchings Subject: Re: [PATCHv2 1/2] net: Allow ethtool to set interface in loopback mode. Date: Thu, 05 May 2011 02:52:48 +0100 Message-ID: <1304560369.3203.44.camel@localhost> References: <1304471935-402-2-git-send-email-maheshb@google.com> <1304559011-15983-1-git-send-email-maheshb@google.com> Mime-Version: 1.0 Content-Type: text/plain; charset="UTF-8" Content-Transfer-Encoding: 7bit Cc: David Miller , netdev , =?UTF-8?Q?Micha=C5=82_Miros=C5=82aw?= , Tom Herbert To: Mahesh Bandewar Return-path: Received: from exchange.solarflare.com ([216.237.3.220]:56525 "EHLO exchange.solarflare.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1752321Ab1EEBww (ORCPT ); Wed, 4 May 2011 21:52:52 -0400 In-Reply-To: <1304559011-15983-1-git-send-email-maheshb@google.com> Sender: netdev-owner@vger.kernel.org List-ID: On Wed, 2011-05-04 at 18:30 -0700, Mahesh Bandewar wrote: > This patch enables ethtool to set the loopback mode on a given interface. > By configuring the interface in loopback mode in conjunction with a policy > route / rule, a userland application can stress the egress / ingress path > exposing the flows of the change in progress and potentially help developer(s) > understand the impact of those changes without even sending a packet out > on the network. > > Following set of commands illustrates one such example - > a) ip -4 addr add 192.168.1.1/24 dev eth1 > b) ip -4 rule add from all iif eth1 lookup 250 > c) ip -4 route add local 0/0 dev lo proto kernel scope host table 250 > d) arp -Ds 192.168.1.100 eth1 > e) arp -Ds 192.168.1.200 eth1 > f) sysctl -w net.ipv4.ip_nonlocal_bind=1 > g) sysctl -w net.ipv4.conf.all.accept_local=1 > # Assuming that the machine has 8 cores > h) taskset 000f netserver -L 192.168.1.200 > i) taskset 00f0 netperf -t TCP_CRR -L 192.168.1.100 -H 192.168.1.200 -l 30 > > Signed-off-by: Mahesh Bandewar Acked-by: Ben Hutchings -- Ben Hutchings, Senior Software Engineer, Solarflare Not speaking for my employer; that's the marketing department's job. They asked us to note that Solarflare product names are trademarked.