From owner-freebsd-net@FreeBSD.ORG Sun Feb 25 14:47:57 2007 Return-Path: X-Original-To: freebsd-net@freebsd.org Delivered-To: freebsd-net@freebsd.org Received: from mx1.freebsd.org (mx1.freebsd.org [69.147.83.52]) by hub.freebsd.org (Postfix) with ESMTP id 6ACB216A404 for ; Sun, 25 Feb 2007 14:47:57 +0000 (UTC) (envelope-from andre@freebsd.org) Received: from c00l3r.networx.ch (c00l3r.networx.ch [62.48.2.2]) by mx1.freebsd.org (Postfix) with ESMTP id D5A5213C46B for ; Sun, 25 Feb 2007 14:47:56 +0000 (UTC) (envelope-from andre@freebsd.org) Received: (qmail 81367 invoked from network); 25 Feb 2007 13:54:35 -0000 Received: from c00l3r.networx.ch (HELO [127.0.0.1]) ([62.48.2.2]) (envelope-sender ) by c00l3r.networx.ch (qmail-ldap-1.03) with SMTP for ; 25 Feb 2007 13:54:35 -0000 Message-ID: <45E19B54.9060007@freebsd.org> Date: Sun, 25 Feb 2007 15:21:08 +0100 From: Andre Oppermann User-Agent: Thunderbird 1.5.0.9 (Windows/20061207) MIME-Version: 1.0 To: Kip Macy References: In-Reply-To: Content-Type: text/plain; charset=ISO-8859-1; format=flowed Content-Transfer-Encoding: 7bit Cc: freebsd-net Subject: Re: improved TSO interface needed 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: Sun, 25 Feb 2007 14:47:57 -0000 Kip Macy wrote: > Evidently FreeBSD violates the LSO spec by sending down up to socket > buffer sized TSO segments to the network card. Is there a way to set > this other than reducing net.inet.tcp.sendbuf_max to a compliant value > (64k)? And is there a way to for a device to communicate to the stack > the maximum length of an mbuf chain? From netinet/ip_output.c: * When doing TSO limit a burst to TCP_MAXWIN minus the * IP, TCP and Options length to keep ip->ip_len from * overflowing. Prevent the last segment from being * fractional thus making them all equal sized and set * the flag to continue sending. TCP_MAXWIN is 64K. -- Andre