From owner-freebsd-net@FreeBSD.ORG Fri Sep 26 03:20:30 2003 Return-Path: <owner-freebsd-net@FreeBSD.ORG> 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 D91FE16A4B3 for <freebsd-net@freebsd.org>; Fri, 26 Sep 2003 03:20:30 -0700 (PDT) Received: from xaqua.tel.fer.hr (xaqua.tel.fer.hr [161.53.19.25]) by mx1.FreeBSD.org (Postfix) with ESMTP id 9CB6B44015 for <freebsd-net@freebsd.org>; Fri, 26 Sep 2003 03:20:29 -0700 (PDT) (envelope-from zec@tel.fer.hr) Received: by xaqua.tel.fer.hr (Postfix, from userid 20006) id 749AC9B646; Fri, 26 Sep 2003 12:20:27 +0200 (CEST) Received: from tel.fer.hr (zg04-034.dialin.iskon.hr [213.191.137.35]) by xaqua.tel.fer.hr (Postfix) with ESMTP id 4FD469B648; Fri, 26 Sep 2003 12:20:09 +0200 (CEST) Message-ID: <3F741269.3A2FF9FC@tel.fer.hr> Date: Fri, 26 Sep 2003 12:18:17 +0200 From: Marko Zec <zec@tel.fer.hr> X-Mailer: Mozilla 4.8 [en] (Windows NT 5.0; U) X-Accept-Language: en MIME-Version: 1.0 To: Roderick van Domburg <r.s.a.vandomburg@student.utwente.nl> References: <000501c3840c$6da6ae60$6ba55982@gog> Content-Type: text/plain; charset=us-ascii Content-Transfer-Encoding: 7bit X-Spam-Status: No, hits=-5.4 required=5.0 tests=AWL,BAYES_10,EMAIL_ATTRIBUTION,QUOTED_EMAIL_TEXT, REFERENCES,REPLY_WITH_QUOTES version=2.55 X-Spam-Level: X-Spam-Checker-Version: SpamAssassin 2.55 (1.174.2.19-2003-05-19-exp) X-Sanitizer: Advosys mail filter cc: freebsd-net@freebsd.org Subject: Re: DEVICE_POLLING together with link0 interrupt offloading? X-BeenThere: freebsd-net@freebsd.org X-Mailman-Version: 2.1.1 Precedence: list List-Id: Networking and TCP/IP with FreeBSD <freebsd-net.freebsd.org> List-Unsubscribe: <http://lists.freebsd.org/mailman/listinfo/freebsd-net>, <mailto:freebsd-net-request@freebsd.org?subject=unsubscribe> List-Archive: <http://lists.freebsd.org/pipermail/freebsd-net> List-Post: <mailto:freebsd-net@freebsd.org> List-Help: <mailto:freebsd-net-request@freebsd.org?subject=help> List-Subscribe: <http://lists.freebsd.org/mailman/listinfo/freebsd-net>, <mailto:freebsd-net-request@freebsd.org?subject=subscribe> X-List-Received-Date: Fri, 26 Sep 2003 10:20:31 -0000 Roderick van Domburg wrote: > Hello everyone, > > Just curious: I just noticed that DEVICE_POLLING works perfectly well with > the interrupt offloading feature of the fxp driver (link0). In my > understanding, both try to improve ``network scheduling'' for lack of better > words - especially under load. Also I now understand that DEVICE_POLLING is > preferred over interrupt offloading, especially on routers. > > But just for the sake of curiosity: what does enabling _both_ bring about to > the network performancy and latency? I'm thinking that latency would be > greatly increased because the poller would often miss the bundled packets. > > What's your take on this? There's no much sense in enabling both the network interface polling mode and fxp interrupt coalescing microcode at the same time, since the polling code disables all network interface interrupts anyway. Moreover, there wouldn't be any additional latency, since the polling routine would extract all incoming packets from inbound DMA rings as soon as they would arrive. Marko