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Date:      Wed, 29 Apr 1998 16:14:51 -0500
From:      Chris Csanady <ccsanady@friley585.res.iastate.edu>
Cc:        current@FreeBSD.ORG
Subject:   freebsd-net mailing list? (Re: Bandwidth throttling etc.)
Message-ID:  <199804292114.QAA00921@friley585.res.iastate.edu>
In-Reply-To: Your message of "Fri, 24 Apr 1998 19:16:36 CDT." <199804250016.TAA01428@friley585.res.iastate.edu> 

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There seems to be a growing interest in networking--would it be possible
to have a freebsd-net mailing list created for technical discussion of
networking?

Aside from that, I have to wonder if the below part of my earlier message
was simply missed, or just plain ignored.  I am describing a serious and
real problem here--something that needs to be dealt with.  It can cause
*horrible* performance for some applications.  Earlier someone posted about
a web server getting 5 transactions/sec.  This also had terrible effects
on our clustering performance until we disabled the delayed acks.  The
problem basically causes throughput to effectively drop to *zero* for
some message sizes.

That being said, my intent is not whine and complain about this until
someone fixes it.  Rather, I would simply like to see some discussion of
the problems..


Chris Csanady 

--

[ talk of increasing cluster size deleted ]

>Whether we use mbufs clusters or whatever, the packets should be
>contiguous.  I think that this in itself causes somewhat of a problem
>with regards to the current socket buffer handling.  Currently, the fact
>that the advertised window is calculated based on the total memory consumed
>by the mbufs--and not only the data, is causing serious performance
>problems.  This interaction with delayed acks is the only Really Bad thing 
>wrong with our stack that I have noticed.
>
>I believe that BSDI has done some work to deal with this by creating an
>m_compress function that collapses wasted space.
 
[ other random networking stuff deleted ]




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