From owner-freebsd-net@FreeBSD.ORG Wed Aug 22 15:39:10 2007 Return-Path: Delivered-To: freebsd-net@freebsd.org Received: from mx1.freebsd.org (mx1.freebsd.org [IPv6:2001:4f8:fff6::34]) by hub.freebsd.org (Postfix) with ESMTP id A58FE16A419 for ; Wed, 22 Aug 2007 15:39:10 +0000 (UTC) (envelope-from cjeker@diehard.n-r-g.com) Received: from diehard.n-r-g.com (diehard.n-r-g.com [62.48.3.9]) by mx1.freebsd.org (Postfix) with ESMTP id 16E6013C4A8 for ; Wed, 22 Aug 2007 15:39:09 +0000 (UTC) (envelope-from cjeker@diehard.n-r-g.com) Received: (qmail 5753 invoked by uid 1001); 22 Aug 2007 15:12:28 -0000 Date: Wed, 22 Aug 2007 17:12:28 +0200 From: Claudio Jeker To: freebsd-net@freebsd.org Message-ID: <20070822151228.GB22194@diehard.n-r-g.com> Mail-Followup-To: Claudio Jeker , freebsd-net@freebsd.org References: <46CC475F.8030505@FreeBSD.org> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: User-Agent: Mutt/1.5.12-2006-07-14 Subject: Re: Route caching ? X-BeenThere: freebsd-net@freebsd.org X-Mailman-Version: 2.1.5 Precedence: list List-Id: Networking and TCP/IP with FreeBSD List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , X-List-Received-Date: Wed, 22 Aug 2007 15:39:10 -0000 On Wed, Aug 22, 2007 at 05:37:50PM +0300, Ivo Vachkov wrote: > Actually there is: > > struct route_in6 ip6_forward_rt; > > that "caches" the last route used (thanks blue !!!) but i think this > technique is pointless in a multiflow traffic. > > Is it reasonable to believe that route caches can improve networking > performance or we should leave it up to the routing table itself ? > Just because you believe that route caches are great doesn't mean it is true. Show some real code and include benchmarks with various workloads (e.g. a core router that is hit by many many many sessions). Until now all caching solutions resulted in very bad performance on busy boxes. Remember ip_fastforward or how was it called? Another example are all crapy L3 switches that burn down if the CAM (chache) is flodded. IMO it is better to make the route lookup faster and forget about caching. -- :wq Claudio