Re: Rewritten TCP reassembly

From: Andrew Gallatin (gallatin_at_cs.duke.edu)
Date: 12/13/04

  • Next message: Andre Oppermann: "Re: per-interface packet filters" 
    Date: Mon, 13 Dec 2004 16:48:35 -0500 (EST)
To: Andre Oppermann <andre@freebsd.org>

    Andre Oppermann writes:

    >
    > I have already the next round in the works which is optimized even more
    > by merging consecutive mbuf chains together (at the moment I have packet
    > segment chains which have a direct pointer to the mbuf at the end of the
    > chain) and which get passed in one go to soappend_stream. This removes
    > the "present" loop and simplifies the general code a bit more again.

    Great.. I've been a little busy, and have only run tests -- I haven't
    even looked at the code ;)

    > With this and two other optimizations I have in mind you should be able
    > to get very close to the theoretical maximum bandwidth of your current
    > 4Gig Myrinet cards.
    >
    > There are a couple of other TCP tweaks that would help your special case
    > some more now though.

    FWIW, the out-of-order frames are a firmware bug that we hope to fix
    soon. Its just icing on the cake that the bug makes such a nice test
    case for you ;)

    With no copy overhead (kttcp), 3.95Gb/sec is easily achievable,
    even in 5-stable with the old TCP reassembly code.

    Drew
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