From owner-freebsd-current@FreeBSD.ORG Sat Nov 17 21:08:11 2007 Return-Path: Delivered-To: freebsd-current@freebsd.org Received: from mx1.freebsd.org (mx1.freebsd.org [IPv6:2001:4f8:fff6::34]) by hub.freebsd.org (Postfix) with ESMTP id 8DF6816A41A for ; Sat, 17 Nov 2007 21:08:11 +0000 (UTC) (envelope-from kip.macy@gmail.com) Received: from wa-out-1112.google.com (wa-out-1112.google.com [209.85.146.177]) by mx1.freebsd.org (Postfix) with ESMTP id 66B8813C45D for ; Sat, 17 Nov 2007 21:08:11 +0000 (UTC) (envelope-from kip.macy@gmail.com) Received: by wa-out-1112.google.com with SMTP id k17so1520606waf for ; Sat, 17 Nov 2007 13:08:03 -0800 (PST) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=gmail.com; s=beta; h=domainkey-signature:received:received:message-id:date:from:to:subject:cc:in-reply-to:mime-version:content-type:content-transfer-encoding:content-disposition:references; bh=TxnQsaW0ZF9qXax/K5K0qHKibFVoKG+8f4oPL25u7Ys=; b=tZIMKaLnmUFMbUzDq2HJ+HprPZz/6fPruHVpZmwhhty7URzWf8rZ+v4aBRJbyEnO69NDhOF0G6GnE/ZkcIrk4m6cFqTMFeMAFlhgscD553FqDJifwhrtZhP+mDg4sZrBGm96zxDA7nXfmkLPAaXrSBzHjqDfNtenIYtgzWORExg= DomainKey-Signature: a=rsa-sha1; c=nofws; d=gmail.com; s=beta; h=received:message-id:date:from:to:subject:cc:in-reply-to:mime-version:content-type:content-transfer-encoding:content-disposition:references; b=eyybwPMsWtRkKBN2pnH2kNW3KsWh6rQCzEnT5QbOBNPzQO4dltJbFEJilk3flJbbCYnHQww5tiN6lP4Q/kyHlJkuYOpRJHrj4h38pYJ0i26q79mGijxT+h4Mx7uFr0MvKutJsOCMLx48OyKpRwjnqMI299K1sEjPBdjUGgl3q6Q= Received: by 10.114.135.1 with SMTP id i1mr8135wad.1195333683470; Sat, 17 Nov 2007 13:08:03 -0800 (PST) Received: by 10.114.13.15 with HTTP; Sat, 17 Nov 2007 13:08:03 -0800 (PST) Message-ID: Date: Sat, 17 Nov 2007 13:08:03 -0800 From: "Kip Macy" To: "Denis Shaposhnikov" In-Reply-To: <20071117213316.499be43b@vlink.ru> MIME-Version: 1.0 Content-Type: text/plain; charset=ISO-8859-1 Content-Transfer-Encoding: 7bit Content-Disposition: inline References: <20071117003504.R31357@mindcrime.int.bit0.com> <20071117213316.499be43b@vlink.ru> Cc: Mike Silbersack , freebsd-current@freebsd.org, Andre Oppermann Subject: Re: bizarre em + TSO + MSS issue in RELENG_7 X-BeenThere: freebsd-current@freebsd.org X-Mailman-Version: 2.1.5 Precedence: list List-Id: Discussions about the use of FreeBSD-current List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , X-List-Received-Date: Sat, 17 Nov 2007 21:08:11 -0000 On Nov 17, 2007 10:33 AM, Denis Shaposhnikov wrote: > On Sat, 17 Nov 2007 00:42:54 -0500 (EST) > Mike Andrews wrote: > > > Has anyone run into problems with MSS not being respected when using > > TSO, specifically on em cards? > > Yes, I wrote about this problem on the beginning of 2007, see > > http://tinyurl.com/3e5ak5 > if_em.c:3502 /* * Payload size per packet w/o any headers. * Length of all headers up to payload. */ TXD->tcp_seg_setup.fields.mss = htole16(mp->m_pkthdr.tso_segsz); TXD->tcp_seg_setup.fields.hdr_len = hdr_len; Please print out the value of tso_segsz here. It appears to be being set correctly. The only thing I can think of is that t_maxopd is not correct. As tso_segsz is correct here: if (tso) { m->m_pkthdr.csum_flags = CSUM_TSO; m->m_pkthdr.tso_segsz = tp->t_maxopd - optlen; } But maxopd appears to be set correctly in tcp_input: mss = min(mss, offer); /* * maxopd stores the maximum length of data AND options * in a segment; maxseg is the amount of data in a normal * segment. We need to store this value (maxopd) apart * from maxseg, because now every segment carries options * and thus we normally have somewhat less data in segments. */ tp->t_maxopd = mss;