From mboxrd@z Thu Jan 1 00:00:00 1970 From: Ben Greear Subject: Re: [PATCH] net: allow netdev_wait_allrefs() to run faster Date: Mon, 09 Aug 2010 11:03:18 -0700 Message-ID: <4C6042E6.3060602@candelatech.com> References: <4ADB55BC.5020107@gmail.com> <20091018182144.GC23395@kvack.org> <200910211539.01824.opurdila@ixiacom.com> <4ADF2B57.4030708@gmail.com> <20091021165139.GL877@kvack.org> <20091029233848.GV3141@kvack.org> <4C603999.1030801@candelatech.com> <20100809173429.GR30010@kvack.org> <4C603E6E.1060309@candelatech.com> <20100809174856.GS30010@kvack.org> Mime-Version: 1.0 Content-Type: text/plain; charset=ISO-8859-1; format=flowed Content-Transfer-Encoding: 7bit Cc: "Eric W. Biederman" , Eric Dumazet , Octavian Purdila , netdev@vger.kernel.org, Cosmin Ratiu To: Benjamin LaHaise Return-path: Received: from mail.candelatech.com ([208.74.158.172]:47440 "EHLO ns3.lanforge.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751029Ab0HISDU (ORCPT ); Mon, 9 Aug 2010 14:03:20 -0400 In-Reply-To: <20100809174856.GS30010@kvack.org> Sender: netdev-owner@vger.kernel.org List-ID: On 08/09/2010 10:48 AM, Benjamin LaHaise wrote: > On Mon, Aug 09, 2010 at 10:44:14AM -0700, Ben Greear wrote: >> We also have a few rules per interface, and notice that it takes around 10ms >> per rule when we are removing them, even when using batching in 'ip': > ... >> Patrick thought had an idea, but I don't think he had time to >> look at it further: >> >> "Its probably the synchronize_rcu() in fib_nl_delrule() and >> the route flushing happening after rule removal." > > Yes, that would be a problem, but the issue is deeper than that -- if I'm > not mistaken it's on the packet processing path that iptables doesn't scale > for 100k interfaces with 1 rule per interface. It's been a while since I > ran the tests, but I don't think it's changed much. It would be nice to tie the rules based on 'iif' to a specific interface. Seems it should give near constant time lookup for rules if we only have a few per interface.... Thanks, Ben -- Ben Greear Candela Technologies Inc http://www.candelatech.com