From owner-freebsd-net@FreeBSD.ORG Tue Apr 24 15:03:58 2012 Return-Path: Delivered-To: net@freebsd.org Received: from mx1.freebsd.org (mx1.freebsd.org [69.147.83.52]) by hub.freebsd.org (Postfix) with ESMTP id 358FF1065674; Tue, 24 Apr 2012 15:03:58 +0000 (UTC) (envelope-from kmacybsd@gmail.com) Received: from mail-iy0-f182.google.com (mail-iy0-f182.google.com [209.85.210.182]) by mx1.freebsd.org (Postfix) with ESMTP id D60D48FC08; Tue, 24 Apr 2012 15:03:57 +0000 (UTC) Received: by iahk25 with SMTP id k25so1465899iah.13 for ; Tue, 24 Apr 2012 08:03:57 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=gmail.com; s=20120113; h=mime-version:sender:in-reply-to:references:date :x-google-sender-auth:message-id:subject:from:to:cc:content-type :content-transfer-encoding; bh=b3VoNSVPsJcux4E5Q+Iw+YOidjKRHdBH/NA92Ntiupk=; b=p0ObvLJARd8bLBj6wc1JAw0TBtARFRYGpWJetkjU0O+lthRG6VER3jR6L5tir8c4mc dZNPsS5v4KzepBrR8WLUSjT9d2V1vD+8auaKfDkTPkuIj6bsY5LuZQs7o1KIyOF3BYF+ Cr782UJUCT1F7r9TtlUfBxRy2g/tFKEELS1z70z0wrGX1ZEaYqY68Dyl0YHjnU0gwjWo QSkGdZWUfVv92kiY3whLRDPQriHyLU7SzaY8w6xxP0thnMan+Ltp+5pjzlx/czhT1hrA oYNI9usWgJCbxblA4Y8xjdpQ+ezNu36gQHdbXPxLrlAyWHOlGORfSg9F5CjUbSd+9jvL 1QQA== MIME-Version: 1.0 Received: by 10.50.168.67 with SMTP id zu3mr1968004igb.28.1335279837392; Tue, 24 Apr 2012 08:03:57 -0700 (PDT) Sender: kmacybsd@gmail.com Received: by 10.50.129.39 with HTTP; Tue, 24 Apr 2012 08:03:57 -0700 (PDT) In-Reply-To: References: <20120419133018.GA91364@onelab2.iet.unipi.it> <4F907011.9080602@freebsd.org> <20120419204622.GA94904@onelab2.iet.unipi.it> <4F96A7C0.3010909@freebsd.org> <20120424140228.GA58809@onelab2.iet.unipi.it> Date: Tue, 24 Apr 2012 17:03:57 +0200 X-Google-Sender-Auth: zs8TRRBPpxUefkZ2_TmpJ7LPH8E Message-ID: From: "K. Macy" To: "Li, Qing" Content-Type: text/plain; charset=windows-1252 Content-Transfer-Encoding: quoted-printable Cc: Luigi Rizzo , "current@freebsd.org" , "net@freebsd.org" Subject: Re: Some performance measurements on the FreeBSD network stack 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: Tue, 24 Apr 2012 15:03:58 -0000 On Tue, Apr 24, 2012 at 4:16 PM, Li, Qing wrote: >> > >From previous tests, the difference between flowtable and >>routing table was small with a single process (about 5% or 50ns >>in the total packet processing time, if i remember well), >>but there was a large gain with multiple concurrent processes. >> > > Yes, that sounds about right when we did the tests a long while ago. > >> >> Removing flowtable increases the cost in ip_output() >> (obviously) but also in ether_output() (because the >> route does not have a lle entry so you need to call >> arpresolve on each packet). >> > > Yup. > >> >> So in revising the route lookup i believe it would be good >> if we could also get at once most of the info that >> ether_output() is computing again and again. >> > > Well, the routing table no longer maintains any lle info, so there > isn't much to copy out the rtentry at the completion of route > lookup. > > If I understood you correctly, you do believe there is a lot of value > in Flowtable caching concept, but you are not suggesting we reverting > back to having the routing table maintain L2 entries, are you ? > One could try a similar conversion of the L2 table to an rmlock without copy while lock is held. -Kip --=20 =A0 =A0=93The real damage is done by those millions who want to 'get by.' The ordinary men who just want to be left in peace. Those who don=92t want their little lives disturbed by anything bigger than themselves. Those with no sides and no causes. Those who won=92t take measure of their own strength, for fear of antagonizing their own weakness. Those who don=92t like to make waves=97or enemies. =A0 =A0Those for whom freedom, honour, truth, and principles are only literature. Those who live small, love small, die small. It=92s the reductionist approach to life: if you keep it small, you=92ll keep it under control. If you don=92t make any noise, the bogeyman won=92t find you. =A0 =A0But it=92s all an illusion, because they die too, those people who roll up their spirits into tiny little balls so as to be safe. Safe?! >From what? Life is always on the edge of death; narrow streets lead to the same place as wide avenues, and a little candle burns itself out just like a flaming torch does. =A0 =A0I choose my own way to burn.=94 =A0 =A0Sophie Scholl