From owner-freebsd-current@FreeBSD.ORG Wed Sep 13 15:46:57 2006 Return-Path: X-Original-To: freebsd-current@freebsd.org Delivered-To: freebsd-current@freebsd.org Received: from mx1.FreeBSD.org (mx1.freebsd.org [216.136.204.125]) by hub.freebsd.org (Postfix) with ESMTP id 365F116A582; Wed, 13 Sep 2006 15:46:57 +0000 (UTC) (envelope-from brooks@lor.one-eyed-alien.net) Received: from sccmmhc91.asp.att.net (sccmmhc91.asp.att.net [204.127.203.211]) by mx1.FreeBSD.org (Postfix) with ESMTP id 6CEF743D5F; Wed, 13 Sep 2006 15:46:53 +0000 (GMT) (envelope-from brooks@lor.one-eyed-alien.net) Received: from lor.one-eyed-alien.net ([12.207.12.9]) by sccmmhc91.asp.att.net (sccmmhc91) with ESMTP id <20060913154646m9100smegse>; Wed, 13 Sep 2006 15:46:52 +0000 Received: from lor.one-eyed-alien.net (localhost [127.0.0.1]) by lor.one-eyed-alien.net (8.13.6/8.13.6) with ESMTP id k8DFkhdG075301; Wed, 13 Sep 2006 10:46:44 -0500 (CDT) (envelope-from brooks@lor.one-eyed-alien.net) Received: (from brooks@localhost) by lor.one-eyed-alien.net (8.13.6/8.13.6/Submit) id k8DFkMqY075300; Wed, 13 Sep 2006 10:46:22 -0500 (CDT) (envelope-from brooks) Date: Wed, 13 Sep 2006 10:46:22 -0500 From: Brooks Davis To: John Baldwin Message-ID: <20060913154622.GA52716@lor.one-eyed-alien.net> References: <7.0.1.0.0.20060912125903.15bdb7a0@sentex.net> <45073F58.6080900@freebsd.org> <200609131108.45382.jhb@freebsd.org> Mime-Version: 1.0 Content-Type: multipart/signed; micalg=pgp-sha1; protocol="application/pgp-signature"; boundary="3V7upXqbjpZ4EhLz" Content-Disposition: inline In-Reply-To: <200609131108.45382.jhb@freebsd.org> User-Agent: Mutt/1.5.11 Cc: Andre Oppermann , current@freebsd.org, Mike Tancsa , Ian FREISLICH , freebsd-current@freebsd.org, Jack Vogel Subject: Re: TSO, SMP and the em driver. 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: Wed, 13 Sep 2006 15:46:57 -0000 --3V7upXqbjpZ4EhLz Content-Type: text/plain; charset=us-ascii Content-Disposition: inline Content-Transfer-Encoding: quoted-printable On Wed, Sep 13, 2006 at 11:08:44AM -0400, John Baldwin wrote: > On Tuesday 12 September 2006 19:14, Andre Oppermann wrote: > > Mike Tancsa wrote: > > > At 12:43 PM 9/12/2006, Andre Oppermann wrote: > > >=20 > > >> TSO !=3D (vlan && promisc) > > >=20 > > > Sorry, the commonality I was referring to was VLAN hardware tagging a= nd=20 > > > how it must be enabled for TSO, but that breaks other things. See a = few=20 > > > messages ago > > >=20 > http://lists.freebsd.org/pipermail/freebsd-current/2006-September/065818.= html=20 > >=20 > > I'm sure we can find a workaround for that. >=20 > Well, you could have the em(4) driver manually handle TSO in software, wh= ich=20 > is what it does to workaround the VLAN tag problem. (It does VLAN=20 > encapsulation in the driver.) While VLAN insertion may be trivial,=20 > re-implementing TCP segmentation in the driver might be a good bit less= =20 > trivial to do. There's not going to be a simple easy workaround for this= =20 > hardware bug. :( I'm not sure it's worth worrying about with GbE hardware. Just disable TSO in promiscuous mode. Where TSO is going to really matter is 10GbE. No supporting TSO in some configurations with GbE doesn't seem like a big deal to me. -- Brooks --3V7upXqbjpZ4EhLz Content-Type: application/pgp-signature Content-Disposition: inline -----BEGIN PGP SIGNATURE----- Version: GnuPG v1.4.5 (FreeBSD) iD8DBQFFCCfNXY6L6fI4GtQRAsM/AJ9k7snMNGRUDq+0Ow0d2SyroGn7GQCgoGTZ DCElhWksL2WnykQFJeUfNnc= =3Ijl -----END PGP SIGNATURE----- --3V7upXqbjpZ4EhLz--