From owner-freebsd-net@FreeBSD.ORG Thu Sep 25 04:05:41 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 D82BD106568C for ; Thu, 25 Sep 2008 04:05:41 +0000 (UTC) (envelope-from julian@elischer.org) Received: from outB.internet-mail-service.net (outb.internet-mail-service.net [216.240.47.225]) by mx1.freebsd.org (Postfix) with ESMTP id C3FDF8FC13 for ; Thu, 25 Sep 2008 04:05:41 +0000 (UTC) (envelope-from julian@elischer.org) Received: from idiom.com (mx0.idiom.com [216.240.32.160]) by out.internet-mail-service.net (Postfix) with ESMTP id 7AE6D2490; Wed, 24 Sep 2008 21:05:42 -0700 (PDT) Received: from julian-mac.elischer.org (localhost [127.0.0.1]) by idiom.com (Postfix) with ESMTP id 476082D6017; Wed, 24 Sep 2008 21:05:41 -0700 (PDT) Message-ID: <48DB0E14.6030607@elischer.org> Date: Wed, 24 Sep 2008 21:05:40 -0700 From: Julian Elischer User-Agent: Thunderbird 2.0.0.16 (Macintosh/20080707) MIME-Version: 1.0 To: gnn@freebsd.org References: <20080924195331.GQ783@funkthat.com> In-Reply-To: Content-Type: text/plain; charset=ISO-8859-1; format=flowed Content-Transfer-Encoding: 7bit Cc: net@freebsd.org 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: Thu, 25 Sep 2008 04:05:41 -0000 gnn@freebsd.org wrote: > 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. > One system I have seen, that I thought made sense used to define queue length globally in msecs and each interface interpretted that to a different length. > Best, > George > _______________________________________________ > freebsd-net@freebsd.org mailing list > http://lists.freebsd.org/mailman/listinfo/freebsd-net > To unsubscribe, send any mail to "freebsd-net-unsubscribe@freebsd.org"