Date: Sat, 31 Aug 2013 19:15:33 -0700 (PDT) From: Barney Cordoba <barney_cordoba@yahoo.com> To: "T.C. Gubatayao" <tgubatayao@barracuda.com>, Luigi Rizzo <rizzo@iet.unipi.it>, Alan Somers <asomers@freebsd.org> Cc: Jack F Vogel <jfv@freebsd.org>, "Justin T. Gibbs" <gibbs@freebsd.org>, Andre Oppermann <andre@freebsd.org>, "net@freebsd.org" <net@freebsd.org> Subject: Re: Flow ID, LACP, and igb Message-ID: <1378001733.36695.YahooMailNeo@web121606.mail.ne1.yahoo.com> In-Reply-To: <BCC2C62D4FE171479E2F1C2593FE508B0BE2440B@BN-SCL-MBX03.Cudanet.local> References: <D01A0CB2-B1E3-4F4B-97FA-4C821C0E3FD2@FreeBSD.org> <521BBD21.4070304@freebsd.org> <CAOtMX2jvKGY==t9i-a_8RtMAPH2p1VDj950nMHHouryoz3nbsA@mail.gmail.com> <521EE8DA.3060107@freebsd.org> <BCC2C62D4FE171479E2F1C2593FE508B0BE24383@BN-SCL-MBX03.Cudanet.local> <CAOtMX2h5SGh5eYV50y%2BQB_s367V9iattGU862wwXcONDV%2BTG8g@mail.gmail.com> <CA%2BhQ2%2BhgTaK1ZCOLGVFjSPY8nyNPHK4waSecyRQxR1gQcyjztg@mail.gmail.com>, <1377952913.44129.YahooMailNeo@web121605.mail.ne1.yahoo.com> <BCC2C62D4FE171479E2F1C2593FE508B0BE2440B@BN-SCL-MBX03.Cudanet.local>
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No, no. The entire point of the hash is to separate the "connections". But when testing you should use realistic assumptions. You're not splitting packets, so the big packets will mess up your distribution if you don't get it right. Of course there's nothing really wrong with OOO packets. We had this discussion before; lots of people have round robin dual homing without any ill effects. It's just not an issue. BC ________________________________ From: T.C. Gubatayao <tgubatayao@barracuda.com> To: Barney Cordoba <barney_cordoba@yahoo.com>; Luigi Rizzo <rizzo@iet.unipi.it>; Alan Somers <asomers@freebsd.org> Cc: Jack F Vogel <jfv@freebsd.org>; Justin T. Gibbs <gibbs@freebsd.org>; Andre Oppermann <andre@freebsd.org>; "net@freebsd.org" <net@freebsd.org> Sent: Saturday, August 31, 2013 9:38 PM Subject: RE: Flow ID, LACP, and igb On Sat, Aug 31, 2013 at 8:41 AM, Barney Cordoba <barney_cordoba@yahoo.com> wrote: > Also, the *most* important thing is distribution with realistic data. The goal > should be to use the most trivial function that gives the most balanced > distribution with real numbers. Faster is not better if the result is an > unbalanced distribution. Agreed, with a caveat. It's critical that this distribution be by "flow", so that out of order packet delivery is minimized. > Many of your ports will be 80 and 53, and if you're going through a router > your ethernets may not be very unique, so why even bother to include them? > Does getting a good distribution require that you hash every element > individually, or can you get the same distribution with a faster, simpler way > of creating the seed? > > There's also the other consideration of packet size. Packets on port 53 are > likely to be smaller than packets on port 80. What you want is equal > distribution PER PORT on the ports that will carry that vast majority of your > traffic. Unfortunately, trying to evenly distribute traffic per port based on packet size will likely result in the reordering of packets, and bandwidth wasted on TCP retransmissions. > Or better yet, use the same number of queues on igb as you have LAGG ports, > and use the queue id (or RSS) as the hash, so that your traffic is sync'd > between the ethernet adapter queues and the LAGG ports. The card has already > done the work for you. Isn't this hash for selecting an outbound link? The ingress adapter hash (RSS) won't help for packets originating from the host, or for packets that may have been translated or otherwise modified while traversing the stack. T.C. _______________________________________________ freebsd-net@freebsd.org mailing list http://lists.freebsd.org/mailman/listinfo/freebsd-net To unsubscribe, send any mail to "freebsd-net-unsubscribe@freebsd.org" From owner-freebsd-net@FreeBSD.ORG Sun Sep 1 02:27:30 2013 Return-Path: <owner-freebsd-net@FreeBSD.ORG> Delivered-To: net@freebsd.org Received: from mx1.freebsd.org (mx1.freebsd.org [IPv6:2001:1900:2254:206a::19:1]) (using TLSv1 with cipher ADH-AES256-SHA (256/256 bits)) (No client certificate requested) by hub.freebsd.org (Postfix) with ESMTP id 26ECF1A9; Sun, 1 Sep 2013 02:27:30 +0000 (UTC) (envelope-from rizzo.unipi@gmail.com) Received: from mail-lb0-x22d.google.com (mail-lb0-x22d.google.com [IPv6:2a00:1450:4010:c04::22d]) (using TLSv1 with cipher ECDHE-RSA-RC4-SHA (128/128 bits)) (No client certificate requested) by mx1.freebsd.org (Postfix) with ESMTPS id BDF532FFD; Sun, 1 Sep 2013 02:27:28 +0000 (UTC) Received: by mail-lb0-f173.google.com with SMTP id o14so2863597lbi.32 for <multiple recipients>; Sat, 31 Aug 2013 19:27:26 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=gmail.com; s 120113; h=mime-version:sender:in-reply-to:references:date:message-id:subject :from:to:cc:content-type; bh=Ylc3iq3b1QlBvxdTgYhUgUqLOYU0kK7Dv2264U9ZG1k=; b=aHY+jNZ7CRomOgDJ0DjWOp9DZwfGq0D2aEaI1E7mBMy2aD0MFFw2z7LDjetbuFI/XL zPiq3hDfcDlZLV6jf041gpCCUHWXMWQJfRxc9+f95a63+xRvrWCfd5coqV1a4XJYT9eq +AMuYXwoaY8XUgaVb0STpTXeXu9kYDP1W1eMRAuRa6O0G5+OvRK3H4VgNagW6CmmZDx+ yJ9Yf/h/FWML3NNiO/sYC7CJyLi1Xi323yKSWMkP2dzXqKrDBVWVjbT3xYP1iuRvFg7g STqhbJxOcjFor3tl8NnRLVrJ6nXpU/d3hFl/hpkf11n6bbklV2xSv3vu1sGFr/15Topc YCEg=MIME-Version: 1.0 X-Received: by 10.152.3.42 with SMTP id 10mr15000594laz.22.1378002445948; Sat, 31 Aug 2013 19:27:25 -0700 (PDT) Sender: rizzo.unipi@gmail.com Received: by 10.114.200.165 with HTTP; Sat, 31 Aug 2013 19:27:25 -0700 (PDT) In-Reply-To: <1378001733.36695.YahooMailNeo@web121606.mail.ne1.yahoo.com> References: <D01A0CB2-B1E3-4F4B-97FA-4C821C0E3FD2@FreeBSD.org> <521BBD21.4070304@freebsd.org> <CAOtMX2jvKGY==t9i-a_8RtMAPH2p1VDj950nMHHouryoz3nbsA@mail.gmail.com> <521EE8DA.3060107@freebsd.org> <BCC2C62D4FE171479E2F1C2593FE508B0BE24383@BN-SCL-MBX03.Cudanet.local> <CAOtMX2h5SGh5eYV50y+QB_s367V9iattGU862wwXcONDV+TG8g@mail.gmail.com> <CA+hQ2+hgTaK1ZCOLGVFjSPY8nyNPHK4waSecyRQxR1gQcyjztg@mail.gmail.com> <1377952913.44129.YahooMailNeo@web121605.mail.ne1.yahoo.com> <BCC2C62D4FE171479E2F1C2593FE508B0BE2440B@BN-SCL-MBX03.Cudanet.local> <1378001733.36695.YahooMailNeo@web121606.mail.ne1.yahoo.com> Date: Sun, 1 Sep 2013 04:27:25 +0200 X-Google-Sender-Auth: uHUCtpiAk6eN9tIh6b_OBc3skCM Message-ID: <CA+hQ2+j-DDuEX1KCDYioCactjL71p-d4AtusPUfePrswDyUpog@mail.gmail.com> Subject: Re: Flow ID, LACP, and igb From: Luigi Rizzo <rizzo@iet.unipi.it> To: Barney Cordoba <barney_cordoba@yahoo.com> Content-Type: text/plain; charset=ISO-8859-1 X-Content-Filtered-By: Mailman/MimeDel 2.1.14 Cc: Andre Oppermann <andre@freebsd.org>, Alan Somers <asomers@freebsd.org>, "net@freebsd.org" <net@freebsd.org>, Jack F Vogel <jfv@freebsd.org>, "Justin T. Gibbs" <gibbs@freebsd.org>, "T.C. Gubatayao" <tgubatayao@barracuda.com> X-BeenThere: freebsd-net@freebsd.org X-Mailman-Version: 2.1.14 Precedence: list List-Id: Networking and TCP/IP with FreeBSD <freebsd-net.freebsd.org> List-Unsubscribe: <http://lists.freebsd.org/mailman/options/freebsd-net>, <mailto:freebsd-net-request@freebsd.org?subject=unsubscribe> List-Archive: <http://lists.freebsd.org/pipermail/freebsd-net>; List-Post: <mailto:freebsd-net@freebsd.org> List-Help: <mailto:freebsd-net-request@freebsd.org?subject=help> List-Subscribe: <http://lists.freebsd.org/mailman/listinfo/freebsd-net>, <mailto:freebsd-net-request@freebsd.org?subject=subscribe> X-List-Received-Date: Sun, 01 Sep 2013 02:27:30 -0000 On Sun, Sep 1, 2013 at 4:15 AM, Barney Cordoba <barney_cordoba@yahoo.com>wrote: > ... > [your point on testing with realistic assumptions is surely a valid one] > > Of course there's nothing really wrong with OOO packets. We had this > discussion before; lots of people > have round robin dual homing without any ill effects. It's just not an > issue. > It depends on where you are. It may not be an issue if the reordering is not large enough to trigger retransmissions, but even then it is annoying as it causes more work in the endpoint -- it prevents LRO from working, and even on the host stack it takes more work to sort where an out of order segment goes than appending an in-order one to the socket buffer. cheers luigi
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