lkml.org 
[lkml]   [2007]   [Oct]   [1]   [last100]   RSS Feed
Views: [wrap][no wrap]   [headers]  [forward] 
 
Messages in this thread
    /
    Date
    SubjectRe: 2.6.21 -> 2.6.22 & 2.6.23-rc8 performance regression
    From
    From: Eric Dumazet <dada1@cosmosbay.com>
    Date: Mon, 01 Oct 2007 22:10:03 +0200

    > So maybe the following patch is necessary...
    >
    > I believe IPV6 & DCCP are immune to this problem.
    >
    > Thanks again Denys for spotting this.
    >
    > Eric
    >
    > [PATCH] TCP : secure_tcp_sequence_number() should not use a too fast clock
    >
    > TCP V4 sequence numbers are 32bits, and RFC 793 assumed a 250 KHz clock.
    > In order to follow network speed increase, we can use a faster clock, but
    > we should limit this clock so that the delay between two rollovers is
    > greater than MSL (TCP Maximum Segment Lifetime : 2 minutes)
    >
    > Choosing a 64 nsec clock should be OK, since the rollovers occur every
    > 274 seconds.
    >
    > Problem spotted by Denys Fedoryshchenko
    >
    > Signed-off-by: Eric Dumazet <dada1@cosmosbay.com>

    Thanks a lot Eric for bringing closure to this.

    I'll apply this and add a reference in the commit message to the
    changeset that introduced this problem, since it might help
    others who look at this.
    -
    To unsubscribe from this list: send the line "unsubscribe linux-kernel" in
    the body of a message to majordomo@vger.kernel.org
    More majordomo info at http://vger.kernel.org/majordomo-info.html
    Please read the FAQ at http://www.tux.org/lkml/

    \
     
     \ /
      Last update: 2007-10-01 22:59    [W:4.548 / U:1.392 seconds]
    ©2003-2020 Jasper Spaans|hosted at Digital Ocean and TransIP|Read the blog|Advertise on this site