From mboxrd@z Thu Jan 1 00:00:00 1970 From: Serge Hallyn Subject: Re: [RFC][PATCH] iproute: Faster ip link add, set and delete Date: Thu, 28 Mar 2013 08:36:52 -0500 Message-ID: <20130328133652.GA6652@sergelap> References: <874nfwri6o.fsf@xmission.com> <20130327104746.0ec9dcb5@nehalam.linuxnetplumber.net> <87620cpd0y.fsf@xmission.com> <20130328032046.GA32083@sergelap> <87vc8cnq6v.fsf@xmission.com> <20130328042808.GA11672@sergelap> <87d2uknmnu.fsf@xmission.com> Mime-Version: 1.0 Content-Type: text/plain; charset=us-ascii Cc: Stephen Hemminger , Benoit Lourdelet , "netdev@vger.kernel.org" To: "Eric W. Biederman" Return-path: Received: from youngberry.canonical.com ([91.189.89.112]:37123 "EHLO youngberry.canonical.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1755715Ab3C1NhA (ORCPT ); Thu, 28 Mar 2013 09:37:00 -0400 Content-Disposition: inline In-Reply-To: <87d2uknmnu.fsf@xmission.com> Sender: netdev-owner@vger.kernel.org List-ID: Quoting Eric W. Biederman (ebiederm@xmission.com): > Serge Hallyn writes: > > > Quoting Eric W. Biederman (ebiederm@xmission.com): > >> Serge Hallyn writes: > >> > >> > Quoting Eric W. Biederman (ebiederm@xmission.com): > >> >> Stephen Hemminger writes: > >> >> > >> >> > If you need to do lots of operations the --batch mode will be significantly faster. > >> >> > One command start and one link map. > >> >> > >> >> The problem in this case as I understand it is lots of independent > >> >> operations. Now maybe lxc should not shell out to ip and perform the > >> >> work itself. > >> > > >> > fwiw lxc uses netlink to create new veths, and picks random names with > >> > mktemp() ahead of time. > >> > >> I am puzzled where does the slownes in iproute2 come into play? > > > > Benoit originally reported slowness when starting >1500 containers. I > > asked him to run a few manual tests to figure out what was taking the > > time. Manually creating a large # of veths was an obvious test, and > > one which showed poorly scaling performance. > > Apparently iproute is involved somehwere as when he tested with a > patched iproute (as you asked him to) the lxc startup slowdown was > gone. > > > May well be there are other things slowing down lxc of course. > > The evidence indicates it was iproute being called somewhere... Benoit can you tell us exactly what test you were running when you saw the slowdown was gone? -serge