From mboxrd@z Thu Jan 1 00:00:00 1970 From: David Miller Subject: Re: [PATCH net-next] net: Allow ethtool to set interface in loopback mode. Date: Wed, 27 Apr 2011 23:08:07 -0700 (PDT) Message-ID: <20110427.230807.48512460.davem@davemloft.net> References: <1303347458-14499-1-git-send-email-maheshb@google.com> Mime-Version: 1.0 Content-Type: Text/Plain; charset=us-ascii Content-Transfer-Encoding: 7bit Cc: netdev@vger.kernel.org To: maheshb@google.com Return-path: Received: from 74-93-104-97-Washington.hfc.comcastbusiness.net ([74.93.104.97]:57674 "EHLO sunset.davemloft.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751821Ab1D1GIk (ORCPT ); Thu, 28 Apr 2011 02:08:40 -0400 In-Reply-To: <1303347458-14499-1-git-send-email-maheshb@google.com> Sender: netdev-owner@vger.kernel.org List-ID: From: Mahesh Bandewar Date: Wed, 20 Apr 2011 17:57:38 -0700 > 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 It's impossible to evaluate this patch without you also showing us some users. I'm not applying this.