wierd dsl performance with -CURRENT

Kenneth Culver culverk at yumyumyum.org
Wed Jul 9 23:44:49 PDT 2003

> This is the data transfer, so the d2c_* plots are the interesting ones
> (they graph the traffic from ftp2 to you).  If you load up d2c_tput.xpl,
> you can see that your throughput averaged ~164K/s for almost the entire
> time.  The red line is the short-term average, and you can see there
> were four dips, corresponding to packet loss.  Flip over to the
> d2c_tsg.xpl plot, which graphs the sent packets, ACKs, and the receive
> window.  At 21:52:32.8, it looks like four consecutive packets were
> dropped.  Luckily, the packets were resent quickly, and transmission
> resumed at full speed.  Dips 3 and 4 look the same.  Dip 2 has an extra
> .2 second delay for some reason.  It looks like fast restransmit kicked
> in on all three dips, but for some reason it didn't recover fast enough
> on #2.  A TCP guru will have to tell you what to do next...

Well, the actual transfer occured around 145 - 150KB/sec according to the
ftp program, normally that is 160KB/sec, and the average is around
10-15KB/sec higher after you factor out at least ftp, tcp, IP, and
ethernet header. My bandwidth monitor dockapp shows around 176-164 when
it's working right, but now it starts really slow and eventually gets to
around the average you saw in the graphs.


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