From owner-p4-projects@FreeBSD.ORG Mon Nov 26 17:35:32 2007 Return-Path: Delivered-To: p4-projects@freebsd.org Received: by hub.freebsd.org (Postfix, from userid 32767) id 2418216A418; Mon, 26 Nov 2007 17:35:32 +0000 (UTC) Delivered-To: perforce@freebsd.org Received: from mx1.freebsd.org (mx1.freebsd.org [IPv6:2001:4f8:fff6::34]) by hub.freebsd.org (Postfix) with ESMTP id B158C16A421 for ; Mon, 26 Nov 2007 17:35:31 +0000 (UTC) (envelope-from sam@errno.com) Received: from ebb.errno.com (ebb.errno.com [69.12.149.25]) by mx1.freebsd.org (Postfix) with ESMTP id 89CFE13C47E for ; Mon, 26 Nov 2007 17:35:31 +0000 (UTC) (envelope-from sam@errno.com) Received: from trouble.errno.com (trouble.errno.com [10.0.0.248]) (authenticated bits=0) by ebb.errno.com (8.13.6/8.12.6) with ESMTP id lAQHDktt004902 (version=TLSv1/SSLv3 cipher=DHE-RSA-AES256-SHA bits=256 verify=NO); Mon, 26 Nov 2007 09:13:48 -0800 (PST) (envelope-from sam@errno.com) Message-ID: <474AFECF.4010402@errno.com> Date: Mon, 26 Nov 2007 09:13:51 -0800 From: Sam Leffler User-Agent: Thunderbird 2.0.0.9 (X11/20071125) MIME-Version: 1.0 To: Robert Watson References: <200711260527.lAQ5RNSw090238@repoman.freebsd.org> <20071126115044.J65286@fledge.watson.org> In-Reply-To: <20071126115044.J65286@fledge.watson.org> Content-Type: text/plain; charset=ISO-8859-1; format=flowed Content-Transfer-Encoding: 7bit X-DCC-Rhyolite-Metrics: o.com; whitelist Cc: Perforce Change Reviews , Kip Macy Subject: Re: PERFORCE change 129544 for review X-BeenThere: p4-projects@freebsd.org X-Mailman-Version: 2.1.5 Precedence: list List-Id: p4 projects tree changes List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , X-List-Received-Date: Mon, 26 Nov 2007 17:35:32 -0000 Robert Watson wrote: > > On Mon, 26 Nov 2007, Kip Macy wrote: > >> http://perforce.freebsd.org/chv.cgi?CH=129544 >> >> Change 129544 by kmacy@kmacy:storage:toestack on 2007/11/26 05:26:43 >> >> disable merging of data into existing mbufs if >> new SB_TOE flag is set > > One of the reasons we compact socket buffers with TCP and other stream > protocols is that if you're dealing with an application/protocol that > spits out data in small chunks (i.e., a series of printfs) and nagel > is disabled, you end up with a series of packets that make quite > inefficient use of mbufs, as the space wasted per chunk of data is > significant. Not only that, we bill for space in socket buffers based > on the space held by the full mbuf, not just the data in the mbuf when > it comes to socket buffer resource limits, so you can rapidly fill up > socket buffer limits without compaction in this type of scenario. I'm > not sure which protocols this would affect, but I'd imagine that > RPC-like protocols supporting asynchronous operation (so that you get > a series of replies and responses in flight at once) might be > relevant, such as IMAP. > > On an unrelated not, if we want a non-coalescing modes for socket > bufferss, we should probably also give it a name like "SB_NOCOALESCE" > rather than something TOE-specific. There used to be a record boundary indication to inhibit coalescing. Sam