RE: Debugging Network Performance

Allen,

With my 200MHz 8260 based board, using kernel 2.4.19-pre7,
I fetch a large file (~50Mb) with ftp, and send it to /dev/null
  get large_file /dev/null
and I obtain the following performance:
  50216878 bytes received in 5.52 seconds (9090508 bytes/s)

About 8977 kbytes/sec! This is around the maximum for a 100Mbps link.

In 10Mbps half duplex, I achieve a

The connection is in half duplex on the board side,
and full duplex on the ftp server (It crosses a switch).
Switching to full duplex for both does not affect the performance.

If the performance drops in 100Mbps full duplex, the problem might be
one of configuration between your BCM switch and the external switch.

Are both ends of the link (between your BCM switch and external switch)
set to auto-negotiation? If you disable auto-negociation on one side
only (you force it in full duplex for example), you should also the other to
full duplex.
That is important, and caused me hours of research. ;-)

Hope this helps.

--------------------------------------------
 Jean-Denis Boyer, B.Eng., System Architect
 Mediatrix Telecom Inc.
 4229 Garlock Street
 Sherbrooke (Québec)
 J1L 2C8  CANADA
 (819)829-8749 x241
--------------------------------------------

** Sent via the linuxppc-embedded mail list. See http://lists.linuxppc.org/

With my 200MHz 8260 based board, using kernel 2.4.19-pre7,
I fetch a large file (~50Mb) with ftp, and send it to /dev/null
  get large_file /dev/null
and I obtain the following performance:
  50216878 bytes received in 5.52 seconds (9090508 bytes/s)

I will check smaller files. I know that there is a nice burst of activity
when the transfer starts. Can you try 100MB+ transfer and see if you still
get the same performance. Perhaps I should try 2.4.19pre7. If I get better
results it sure helps to narrow the search for likely suspects. I will also
try piping to /dev/null.

If the performance drops in 100Mbps full duplex, the problem might be
one of configuration between your BCM switch and the external switch.
Are both ends of the link (between your BCM switch and external switch)
set to auto-negotiation?

The switch is a LinkSys 5 port 10/100 switch. (no configuration options that
I am aware of) All ports on the BCM should be in auto-negotiate mode. In a
previous version I printed the negotiation status of each port and it showed
100, full-duplex.

Thanks for the pointers. Based on the emails that I have received, I am not
the only one with this problem. Hopefully we can reproduce your results and
provide some feedback to the group.


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