From owner-freebsd-net@FreeBSD.ORG Wed Nov 21 01:15:34 2012 Return-Path: Delivered-To: freebsd-net@freebsd.org Received: from mx1.freebsd.org (mx1.freebsd.org [69.147.83.52]) by hub.freebsd.org (Postfix) with ESMTP id ADD1E866 for ; Wed, 21 Nov 2012 01:15:34 +0000 (UTC) (envelope-from khatfield@socllc.net) Received: from smtp151.dfw.emailsrvr.com (smtp151.dfw.emailsrvr.com [67.192.241.151]) by mx1.freebsd.org (Postfix) with ESMTP id 697678FC08 for ; Wed, 21 Nov 2012 01:15:34 +0000 (UTC) Received: from localhost (localhost.localdomain [127.0.0.1]) by smtp5.relay.dfw1a.emailsrvr.com (SMTP Server) with ESMTP id DE6821909BC; Tue, 20 Nov 2012 20:08:40 -0500 (EST) X-Virus-Scanned: OK Received: by smtp5.relay.dfw1a.emailsrvr.com (Authenticated sender: khatfield-AT-socllc.net) with ESMTPSA id 63A2D1909CC; Tue, 20 Nov 2012 20:08:40 -0500 (EST) Content-Type: text/plain; charset=us-ascii Content-Transfer-Encoding: quoted-printable Subject: Re: FreeBSD boxes as a 'router'... References: <1353448328.76219.YahooMailClassic@web121602.mail.ne1.yahoo.com> <50AC08EC.8070107@mu.org> From: khatfield@socllc.net Mime-Version: 1.0 In-Reply-To: <50AC08EC.8070107@mu.org> Message-Id: <832757660.33924.1353460119408@238ae4dab3b4454b88aea4d9f7c372c1.nuevasync.com> Date: Tue, 20 Nov 2012 19:08:33 -0600 To: Alfred Perlstein X-NS-Received: from Apple-iPhone5C2/1001.525(khatfield@socllc.net) SECURED(HTTPS); Wed, 21 Nov 2012 01:08:35 +0000 (UTC) Cc: Barney Cordoba , Jim Thompson , "freebsd-net@freebsd.org" X-BeenThere: freebsd-net@freebsd.org X-Mailman-Version: 2.1.14 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, 21 Nov 2012 01:15:34 -0000 Barney - I would certainly love to see some real evidence to backup such a = ridiculous claim. I agree here as well with Jim. I have a ton of experience with and without.= I haven't done enough testing with FreeBSD 9 to state 100% but I can state= that extensive testing and filtering traffic (specifically high PPS DDoS t= raffic) and polling is a requirement in certain situations.=20 It should not be required for normal traffic, certainly under 200Mbps but i= n no way should polling be discounted completely. Tuning Intel NICs works t= o an extent but offloading everything to the NIC without polling is a sure = fire way to live-lock a system in high PPS situations. So anyway, I stick to my original assessment that it can be iffy depending = on volume and scenario but I will also state that throwing polling out comp= letely discounts one of the strengths easily available on FreeBSD. That wou= ld be short-sighted, in my opinion. My recommendation is to use polling if you begin seeing lag or live-lock. I= n general use it isn't required but I assure you it can be extremely helpfu= l or detrimental. It all depends on the application of the system and the t= ype of workload it has. -Kevin On Nov 20, 2012, at 4:49 PM, "Alfred Perlstein" wrote: > On 11/20/12 2:42 PM, Jim Thompson wrote: >> On Nov 20, 2012, at 3:52 PM, Barney Cordoba w= rote: >>=20 >>> Anyone who even mentions polling should be discounted altogether. Polli= ng >>> had value when you couldn't control the interrupt delays; but interrupt >>> moderation allows you to pace the interrupts any way you like without >>> the inefficiencies of polling. >> You're entitled to your opinion, but experimental results have tended to= show yours incorrect. >>=20 >> Jim > Agree with Jim. If you want pure packet performance you burn a core to r= un a polling loop. >=20 > -Alfred