On Tue, Mar 18, 2003 at 01:28:31PM -0800, Ed Mooring wrote:
...
> I had something vaguely similar happen while I was porting the FreeBSD
> 4.2 networking stack to LynxOS. It turned out the culprit was sbappend().
> It does a linear pointer chase down the mbuf chain each time you do
> a write() or send(). With a high bandwidth-delay product, that chain
> can get very long.
>
> This topic came up on freebsd-net last July, and Luigi Rizzo provided
> the following URL for a patch to cache the end of the mbuf chain, so
> sbappend() stays O(1) instead of O(n).
the patch was only for UDP though. I think the poster was seeing the problem
with TCP (which is also affected by the same thing).
cheers
luigi
> http://docs.freebsd.org/cgi/getmsg.cgi?fetch=366972+0+archive/2001/freebsd-net/20010211.freebsd-net
>
> The subject of the July thread was 'the incredible shrinking socket', if
> you want to hunt through the archives.
>
> Hope this helps.
>
> --
> Ed Mooring ([EMAIL PROTECTED])
>
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