From owner-freebsd-net@FreeBSD.ORG Wed Nov 17 19:00:59 2004 Return-Path: Delivered-To: freebsd-net@freebsd.org Received: from mx1.FreeBSD.org (mx1.freebsd.org [216.136.204.125]) by hub.freebsd.org (Postfix) with ESMTP id 7F08B16A4D8 for ; Wed, 17 Nov 2004 19:00:59 +0000 (GMT) Received: from comp.chem.msu.su (comp.chem.msu.su [158.250.32.97]) by mx1.FreeBSD.org (Postfix) with ESMTP id AAA7643D4C for ; Wed, 17 Nov 2004 19:00:40 +0000 (GMT) (envelope-from yar@comp.chem.msu.su) Received: from comp.chem.msu.su (localhost [127.0.0.1]) by comp.chem.msu.su (8.12.9p2/8.12.9) with ESMTP id iAHJ0ZUf052377; Wed, 17 Nov 2004 22:00:35 +0300 (MSK) (envelope-from yar@comp.chem.msu.su) Received: (from yar@localhost) by comp.chem.msu.su (8.12.9p2/8.12.9/Submit) id iAHJ0YWm052376; Wed, 17 Nov 2004 22:00:34 +0300 (MSK) (envelope-from yar) Date: Wed, 17 Nov 2004 22:00:34 +0300 From: Yar Tikhiy To: Eugene Grosbein Message-ID: <20041117190034.GA52103@comp.chem.msu.su> References: <20041117181351.GA48071@comp.chem.msu.su> <20041117185248.GA1394@grosbein.pp.ru> Mime-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20041117185248.GA1394@grosbein.pp.ru> User-Agent: Mutt/1.5.6i cc: net@freebsd.org Subject: Re: polling(4) rocks! X-BeenThere: freebsd-net@freebsd.org X-Mailman-Version: 2.1.1 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, 17 Nov 2004 19:00:59 -0000 On Thu, Nov 18, 2004 at 01:52:49AM +0700, Eugene Grosbein wrote: > On Wed, Nov 17, 2004 at 09:13:51PM +0300, Yar Tikhiy wrote: > > > The router box is a 1.4GHz Celeron PC with an fxp(4) interface split > > across a dozen of vlans. There is nothing special about its setup > > except for ~250 rules loaded into ipfw2. It is running 4.10-RELEASE. > > Without polling, it was able to switch full 10Mbytes/sec of traffic > > (~9kpps), but that took from 50 to 70% CPU time spent in interrupts. > > With polling on, interrupt time never exceeds 5% and it stays as low > > as 1-2% on average even when traffic is that high. > > Does polling(4) increase latency? It is very imortant for router > that handles lots of RTP (VoIP) traffic. I did no tests of latency, but I guess that polling(4) may even decrease it in certain cases due to lower overhead of handling traffic. Of course, that should be tested in practice, but alas, we neither run nor use real-time network services here. -- Yar