Re: Network speed Linux-2.6.10

From: linux-os
Date: Tue Mar 01 2005 - 15:30:27 EST


On Tue, 1 Mar 2005, Ben Greear wrote:

linux-os wrote:

Conditions:

Intel NIC e100 device driver. Two identical machines.
Private network, no other devices. Connected using a Netgear switch.
Test data is the same thing sent from memory on one machine
to a discard server on another, using TCP/IP SOCK_STREAM.

If I set both machines to auto-negotiation OFF and half duplex,
I get about 9 to 9.5 megabytes/second across the private wire
network.

If I set one machine to full duplex and the other to half-duplex
I get 10 to 11 megabytes/second transfer across the network,
regardless of direction.

That is asking for all sorts of trouble.

If I set both machines to auto-negotiation OFF and full duplex,
I get 300 to 400 kilobytes/second regardless of the direction.

Check for errors in the NICs counters (/proc/net/dev/) in this case.
It appears it is not actually set to full-duplex, or maybe it's
10Mbps-FD. Use ethtool to see the actual settings.


I supplied the actual settings.

What happens if you just don't muck with the NIC and let it auto-negotiate
on it's own?


It goes to half-duplex and runs 9 to 9.5 megabytes/second as stated
above.

That's why I think 1/2 duplex is __really__ full-duplex.

Ben


--
Ben Greear <greearb@xxxxxxxxxxxxxxx>
Candela Technologies Inc http://www.candelatech.com


Cheers,
Dick Johnson
Penguin : Linux version 2.6.10 on an i686 machine (5537.79 BogoMips).
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