Date: Sat, 31 Aug 2013 18:38:12 -0700 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> Subject: RE: Flow ID, LACP, and igb Message-ID: <BCC2C62D4FE171479E2F1C2593FE508B0BE2440B@BN-SCL-MBX03.Cudanet.local> In-Reply-To: <1377952913.44129.YahooMailNeo@web121605.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%2BQB_s367V9iattGU862wwXcONDV%2BTG8g@mail.gmail.com> <CA%2BhQ2%2BhgTaK1ZCOLGVFjSPY8nyNPHK4waSecyRQxR1gQcyjztg@mail.gmail.com>, <1377952913.44129.YahooMailNeo@web121605.mail.ne1.yahoo.com>
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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 route= r > 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 a= re > 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 port= s, > 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 alre= ady > 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 h= ave been translated or otherwise modified while traversing the stack. T.C.=
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