From mboxrd@z Thu Jan 1 00:00:00 1970 From: Rick Jones Subject: Re: [iproute PATCH 0/2] Netns performance improvements Date: Thu, 7 Jul 2016 10:28:47 -0700 Message-ID: <577E914F.3060001@hpe.com> References: <1467729773-16751-1-git-send-email-phil@nwl.cc> <87twg4ywjz.fsf@x220.int.ebiederm.org> <20160705205103.GE620@orbyte.nwl.cc> <87h9c259ip.fsf@x220.int.ebiederm.org> <20160707111718.GL620@orbyte.nwl.cc> <577E5244.8030601@6wind.com> <20160707154809.GN620@orbyte.nwl.cc> <577E8054.6040603@hpe.com> <87vb0h1k6b.fsf@x220.int.ebiederm.org> Mime-Version: 1.0 Content-Type: text/plain; charset=utf-8; format=flowed Content-Transfer-Encoding: 7bit Cc: Phil Sutter , Nicolas Dichtel , Stephen Hemminger , netdev@vger.kernel.org To: "Eric W. Biederman" Return-path: Received: from g2t2353.austin.hpe.com ([15.233.44.26]:46946 "EHLO g2t2353.austin.hpe.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751588AbcGGR2t (ORCPT ); Thu, 7 Jul 2016 13:28:49 -0400 In-Reply-To: <87vb0h1k6b.fsf@x220.int.ebiederm.org> Sender: netdev-owner@vger.kernel.org List-ID: On 07/07/2016 09:34 AM, Eric W. Biederman wrote: > Rick Jones writes: >> 300 routers is far from the upper limit/goal. Back in HP Public >> Cloud, we were running as many as 700 routers per network node (*), >> and more than four network nodes. (back then it was just the one >> namespace per router and network). Mileage will of course vary based >> on the "oomph" of one's network node(s). > > To clarify processes for these routers and dhcp servers are created > with "ip netns exec"? I believe so, but it would be good to have someone else confirm that, and speak to your paragraph below. > If that is the case and you are using this feature as effectively a > lightweight container and not lots vrfs in a single network stack > then I suspect much larger gains can be had by creating a variant > of ip netns exec avoids the mount propagation. > ... >> * Didn't want to go much higher than that because each router had a >> port on a common linux bridge and getting to > 1024 would be an >> unpleasant day. > > * I would have thought all you have to do is bump of the size > of the linux neighbour cache. echo $BIGNUM > /proc/sys/net/ipv4/neigh/default/gc_thresh3 We didn't want to hit the 1024 port limit of a (then?) Linux bridge. rick Having a bit of deja vu but I suspect things like commit 0818bf27c05b2de56c5b2bd08cfae2a939bd5f52 are not exactly on the same wavelength, just my brain seeing "namespaces" and "performance" and lighting-up :)