[OpenAFS-devel] .35 sec rx delay bug?

[Ken Hornstein]

>  350ms is the minimum retransmit delay. Is it possible that your network is 
>  dropping packets?
>
>It's possible, and I'll check.  But a 10MB file takes 2 seconds to transfer
>using ssh over tcp, and over 4 minutes using afs over rx over udp.  Is rx
>really that much worse than tcp?

I saw a paper that Sine Nomine did for a customer on AFS client
performance (the work is in the public domain, but it's actually rather
hard to find a copy of this paper).  One thing they discovered is that
when network performance went above 100 megabits, Rx throughput fell off
erratically (on Gig-E, they observed an average throughput of 15 Mb/s).
So yes ... rx really is that much worse than TCP.  I suspect that this
is a long-standing bug that has only manifested itself recently with the
advent of faster disks and network.

--Ken