From mboxrd@z Thu Jan 1 00:00:00 1970 From: David Miller Subject: Re: [PATCHv2 1/2] net: Allow ethtool to set interface in loopback mode. Date: Sun, 08 May 2011 16:00:07 -0700 (PDT) Message-ID: <20110508.160007.212698129.davem@davemloft.net> References: <1304471935-402-2-git-send-email-maheshb@google.com> <1304559011-15983-1-git-send-email-maheshb@google.com> <1304560369.3203.44.camel@localhost> Mime-Version: 1.0 Content-Type: Text/Plain; charset=us-ascii Content-Transfer-Encoding: 7bit Cc: maheshb@google.com, netdev@vger.kernel.org, mirq-linux@rere.qmqm.pl, therbert@google.com To: bhutchings@solarflare.com Return-path: Received: from 74-93-104-97-Washington.hfc.comcastbusiness.net ([74.93.104.97]:43583 "EHLO sunset.davemloft.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1755542Ab1EHXAk (ORCPT ); Sun, 8 May 2011 19:00:40 -0400 In-Reply-To: <1304560369.3203.44.camel@localhost> Sender: netdev-owner@vger.kernel.org List-ID: From: Ben Hutchings Date: Thu, 05 May 2011 02:52:48 +0100 > 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 Applied.