[OpenAFS] Heavy performance loss on gigabit ethernet

[Chaskiel M Grundman]

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--On Monday, August 16, 2004 15:45:27 -0400 Derrick J Brashear
<shadow@dementia.org> wrote:

> About the only thing I can think of which is relevant is some time ago,
> Chaskiel observed a problem here where if the latency was too *low*, some
> calculation in Rx seemed to not work correctly.

The problem is in the calculation of the rtt (round trip time) and
retransmit timeout. If the rtt is 0, then it is considered not initialized,
and the timeout is set to 2 or 3 seconds (depending on whether the server
is considered 'local' to the client), whereas if the rtt is low, but
non-zero, the timeout can drop as low as 0.35 seconds. You can examine the
rtt and timeout values of an rx server or client using the -peers switch of
the rxdebug command.




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