From owner-freebsd-stable@FreeBSD.ORG Mon Aug 26 07:06:54 2013 Return-Path: Delivered-To: freebsd-stable@freebsd.org Received: from mx1.freebsd.org (mx1.freebsd.org [8.8.178.115]) (using TLSv1 with cipher ADH-AES256-SHA (256/256 bits)) (No client certificate requested) by hub.freebsd.org (Postfix) with ESMTP id F2921970 for ; Mon, 26 Aug 2013 07:06:54 +0000 (UTC) (envelope-from h.schmalzbauer@omnilan.de) Received: from s1.omnilan.de (s1.omnilan.de [217.91.127.234]) (using TLSv1 with cipher DHE-RSA-AES256-SHA (256/256 bits)) (No client certificate requested) by mx1.freebsd.org (Postfix) with ESMTPS id 6669B2D21 for ; Mon, 26 Aug 2013 07:06:54 +0000 (UTC) Received: from titan.inop.wdn.omnilan.net (titan.inop.wdn.omnilan.net [172.21.3.1]) (authenticated bits=0) by s1.omnilan.de (8.13.8/8.13.8) with ESMTP id r7Q76huN023138 (version=TLSv1/SSLv3 cipher=DHE-RSA-AES256-SHA bits=256 verify=NO); Mon, 26 Aug 2013 09:06:44 +0200 (CEST) (envelope-from h.schmalzbauer@omnilan.de) Message-ID: <521AFE7E.2040705@omnilan.de> Date: Mon, 26 Aug 2013 09:06:38 +0200 From: Harald Schmalzbauer Organization: OmniLAN User-Agent: Mozilla/5.0 (X11; U; FreeBSD i386; de-DE; rv:1.9.2.8) Gecko/20100906 Lightning/1.0b2 Thunderbird/3.1.2 MIME-Version: 1.0 To: freebsd-stable@freebsd.org Subject: if_em, legacy nic and GbE saturation X-Enigmail-Version: 1.1.2 Content-Type: multipart/signed; micalg=pgp-sha1; protocol="application/pgp-signature"; boundary="------------enigD5E68D27A12A0C935A3A0037" X-BeenThere: freebsd-stable@freebsd.org X-Mailman-Version: 2.1.14 Precedence: list List-Id: Production branch of FreeBSD source code List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , X-List-Received-Date: Mon, 26 Aug 2013 07:06:55 -0000 This is an OpenPGP/MIME signed message (RFC 2440 and 3156) --------------enigD5E68D27A12A0C935A3A0037 Content-Type: text/plain; charset=ISO-8859-15 Content-Transfer-Encoding: quoted-printable Hello, I recycled an older box and put an i350-2 together with a second 82541GI (PCI-slot, one already on-board) into it. The two i350-ports are used with VMDq for ESXi5.1. The two 82541GI are used as lagg-nics by a 9.2-RC (amd64) guest as passthrou PCI device. Always had good results with such setups, but found out, that nics which use the legacy driver part of if_em max out at ~0.6Gbits/s (1500 MTU). There's another NIC on board of this recycle-box, a 82566-PHY (ICH9 integrated MAC). This one uses also if_em, but not legacy code, it reports version 7.3.8 (compared to 1.0.6). And it has no problem fully saturating GbE (~925Mbits/s, no jumbo Frames support anyways). I'm using iperf, with and without lagg (doesn't change anyhing, like it doesn't influence tests on some other boxes with 82576 and i350 (igb)) I see enough idle cycles so CPU shouldn't limit the legacy if_em nics. Also, I see the 82541 consuming arround 8k irqs. Same does the 82566-PHY, but with much higher throughput... I'd like to know if I can't generally expect to saturate older (PCI) GbE nics the line for any reason... I can remember tigeon cards from more than a decade ago, which indeed seemd to lack the performance to gain GbE, but I thought that was no issue shortly later and no "modern" Intel-GbE card had such constraints!? Is there any special tuning for legacy if_em (no need for any TCP tuning, 82566 doesn't have any issue)? Thanks, -Harry --------------enigD5E68D27A12A0C935A3A0037 Content-Type: application/pgp-signature; name="signature.asc" Content-Description: OpenPGP digital signature Content-Disposition: attachment; filename="signature.asc" -----BEGIN PGP SIGNATURE----- Version: GnuPG v2.0.18 (FreeBSD) iEYEARECAAYFAlIa/oMACgkQLDqVQ9VXb8hOGgCgpr/IGqH1zfmwOUuAMMA3bJXT 1J8AnRzwq89uWdIEUC5krugJEU8V645k =sDBx -----END PGP SIGNATURE----- --------------enigD5E68D27A12A0C935A3A0037--