From mboxrd@z Thu Jan 1 00:00:00 1970 From: Benjamin LaHaise Subject: Re: kernel mode pppoe ppp if + ifb + mirred redirect, ethernet packets in ifb?! Date: Tue, 13 Oct 2009 10:34:32 -0400 Message-ID: <20091013143432.GJ6843@kvack.org> References: <200910121143.39924.denys@visp.net.lb> <200910130144.04910.denys@visp.net.lb> <1255436477.6305.2.camel@dogo.mojatatu.com> <200910131545.36946.denys@visp.net.lb> <1255438959.6305.13.camel@dogo.mojatatu.com> Mime-Version: 1.0 Content-Type: text/plain; charset=us-ascii Cc: Denys Fedoryschenko , netdev@vger.kernel.org To: jamal Return-path: Received: from kanga.kvack.org ([205.233.56.17]:39982 "EHLO kanga.kvack.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1759903AbZJMPKV (ORCPT ); Tue, 13 Oct 2009 11:10:21 -0400 Content-Disposition: inline In-Reply-To: <1255438959.6305.13.camel@dogo.mojatatu.com> Sender: netdev-owner@vger.kernel.org List-ID: Hi folks, On Tue, Oct 13, 2009 at 09:02:38AM -0400, jamal wrote: > On Tue, 2009-10-13 at 15:45 +0300, Denys Fedoryschenko wrote: > > Another bottleneck is u32 (i can optimize but) and some strange locks > > appearing at top of perf, maybe same as logon case. > > like you say u32 can be optimized > > > And yes, pppd also appearing, but seems just registering new sysctls (for new > > interface?) takes a lot of resources. > > > > back in the days (when i was involved in pppoe) pppd was a big problem > because it was not rentrant, so to solve the problem you exec a new > process for each user.. > Ben Lahaise did a lot of work in this area and i am pretty sure decided > not to use pppd. Yes, I've been maintaining the ppp implementation (Babylon) initially written by SpellCaster back in '98. My main focus of late has been dealing with PPPoE and L2TP, and specifically with terminating a lot of L2TP LNS traffic. Babylon itself scales fairly well to large numbers of interfaces, as does the network stack these days. Currently the bottleneck in interface creation is in the sysctl code. The other big problem with large numbers of interfaces is interface deletion. The synchronize_rcu() call in the interface teardown ends up making a single daemon with thousands of interfaces take a long time to clean up after itself. -ben