From owner-freebsd-net@FreeBSD.ORG Wed Sep 24 22:04:51 2008 Return-Path: Delivered-To: net@freebsd.org Received: from mx1.freebsd.org (mx1.freebsd.org [IPv6:2001:4f8:fff6::34]) by hub.freebsd.org (Postfix) with ESMTP id CDD4D1065688 for ; Wed, 24 Sep 2008 22:04:51 +0000 (UTC) (envelope-from gnn@neville-neil.com) Received: from proxy.meer.net (proxy.meer.net [64.13.141.13]) by mx1.freebsd.org (Postfix) with ESMTP id A6D8E8FC13 for ; Wed, 24 Sep 2008 22:04:51 +0000 (UTC) (envelope-from gnn@neville-neil.com) Received: from mail.meer.net (mail.meer.net [64.13.141.3]) by proxy.meer.net (8.14.2/8.14.2) with ESMTP id m8OM4lYO001554; Wed, 24 Sep 2008 15:04:51 -0700 (PDT) (envelope-from gnn@neville-neil.com) Received: from mail2.meer.net (mail2.meer.net [64.13.141.16]) by mail.meer.net (8.13.3/8.13.3/meer) with ESMTP id m8OM1tit013731; Wed, 24 Sep 2008 15:01:55 -0700 (PDT) (envelope-from gnn@neville-neil.com) Received: from minion.local.neville-neil.com (209.249.190.254.available.above.net [209.249.190.254] (may be forged)) (authenticated bits=0) by mail2.meer.net (8.14.1/8.14.1) with ESMTP id m8OM1sgS014561; Wed, 24 Sep 2008 15:01:55 -0700 (PDT) (envelope-from gnn@neville-neil.com) Date: Wed, 24 Sep 2008 18:01:53 -0400 Message-ID: From: gnn@freebsd.org To: gnn@freebsd.org, net@freebsd.org In-Reply-To: <20080924195331.GQ783@funkthat.com> References: <20080924195331.GQ783@funkthat.com> User-Agent: Wanderlust/2.15.5 (Almost Unreal) SEMI/1.14.6 (Maruoka) FLIM/1.14.9 (=?ISO-8859-4?Q?Goj=F2?=) APEL/10.7 Emacs/22.2.50 (i386-apple-darwin9.4.0) MULE/5.0 (SAKAKI) MIME-Version: 1.0 (generated by SEMI 1.14.6 - "Maruoka") Content-Type: text/plain; charset=US-ASCII X-Canit-CHI2: 0.50 X-Bayes-Prob: 0.5 (Score 0, tokens from: ) X-Spam-Score: 0.10 () [Tag at 5.00] COMBINED_FROM X-CanItPRO-Stream: default X-Canit-Stats-ID: 1669417 - b9d9db906f29 X-Scanned-By: CanIt (www . roaringpenguin . com) on 64.13.141.13 Cc: Subject: Re: Proposed patch, convert IFQ_MAXLEN to kernel tunable... 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, 24 Sep 2008 22:04:51 -0000 At Wed, 24 Sep 2008 12:53:31 -0700, John-Mark Gurney wrote: > > George V. Neville-Neil wrote this message on Tue, Sep 23, 2008 at 15:29 -0400: > > It turns out that the last time anyone looked at this constant was > > before 1994 and it's very likely time to turn it into a kernel > > tunable. On hosts that have a high rate of packet transmission > > packets can be dropped at the interface queue because this value is > > too small. Rather than make a sweeping code change I propose the > > following change to the macro and updating a couple of places in the > > IP and IPv6 stacks that were using this macro to set their own global > > variables. > > The better solution is to resurrect rwatson's patch that eliminates the > interface queue, and does direct dispatch to the ethernet driver.. > Usually the driver has a queue of 512 or more packets already, so putting > them into a second queue doesn't provide much benefit besides increasing > the amount of locking necessary to deliver packets... Actually I am making this change because I found on 10G hardware the queue is too small. Also, there are many systems where you might want to up this, usually ones that are highly biased towards transmit only, like a multicast repeater of some sort. Best, George