From mboxrd@z Thu Jan 1 00:00:00 1970 From: ebiederm@xmission.com (Eric W. Biederman) Subject: Re: [RFC][PATCH] iproute: Faster ip link add, set and delete Date: Thu, 28 Mar 2013 17:25:46 -0700 Message-ID: <87ppyj6ohh.fsf@xmission.com> References: <20130328150410.GA22789@sergelap> <20130328152040.2c905ad9@nehalam.linuxnetplumber.net> <87zjxn84ks.fsf@xmission.com> <1364516016.15753.59.camel@edumazet-glaptop> Mime-Version: 1.0 Content-Type: text/plain Cc: Stephen Hemminger , Benoit Lourdelet , Serge Hallyn , "netdev\@vger.kernel.org" To: Eric Dumazet Return-path: Received: from out03.mta.xmission.com ([166.70.13.233]:43963 "EHLO out03.mta.xmission.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1753283Ab3C2AZ4 (ORCPT ); Thu, 28 Mar 2013 20:25:56 -0400 In-Reply-To: <1364516016.15753.59.camel@edumazet-glaptop> (Eric Dumazet's message of "Thu, 28 Mar 2013 17:13:36 -0700") Sender: netdev-owner@vger.kernel.org List-ID: Eric Dumazet writes: > On Thu, 2013-03-28 at 16:52 -0700, Eric W. Biederman wrote: > >> On my microbenchmark of just creating 5000 veth pairs this takes pairs >> 16s instead of 13s of my earlier hacks but that is well down in the >> usable range. > > I guess most of the time is taken by sysctl_check_table() All of the significant sysctl slowdowns were fixed in 3.4. If you see something of sysctl show up in a trace I would be happy to talk about it. The kernel side seems to be creating N network devices seems to take NlogN time now. Both sysfs and sysctl store directories as rbtrees removing their previous bottlenecks. The loop I timed at 16s was just: time for i in $(seq 1 5000) ; do ip link add a$i type veth peer name b$i; done There is plenty of room for inefficiencies in 10000 network devices and 5000 forks+execs. Eric