From mboxrd@z Thu Jan 1 00:00:00 1970 From: Ben Hutchings Subject: Re: [PATCH v2] net: Allow ethtool to set interface in loopback mode. Date: Wed, 05 Jan 2011 01:21:44 +0000 Message-ID: <1294190504.2992.3.camel@localhost> References: <1294187401-4662-1-git-send-email-maheshb@google.com> <20110104163645.0b3a3687@nehalam> Mime-Version: 1.0 Content-Type: text/plain; charset="UTF-8" Content-Transfer-Encoding: 7bit Cc: Mahesh Bandewar , David Miller , Laurent Chavey , Tom Herbert , netdev To: Stephen Hemminger Return-path: Received: from exchange.solarflare.com ([216.237.3.220]:48746 "EHLO exchange.solarflare.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751010Ab1AEBVv (ORCPT ); Tue, 4 Jan 2011 20:21:51 -0500 In-Reply-To: <20110104163645.0b3a3687@nehalam> Sender: netdev-owner@vger.kernel.org List-ID: On Tue, 2011-01-04 at 16:36 -0800, Stephen Hemminger wrote: > On Tue, 4 Jan 2011 16:30:01 -0800 > 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 > > Reviewed-by: Ben Hutchings > > Since this is a boolean it SHOULD go into ethtool_flags rather than > being a high level operation. It could do, but I though ETHTOOL_{G,S}FLAGS were intended for controlling offload features. Ben. -- Ben Hutchings, Senior Software Engineer, Solarflare Communications Not speaking for my employer; that's the marketing department's job. They asked us to note that Solarflare product names are trademarked.