Re: Xircom RealPort versus 3COM 3C3FEM656C

[Ion Badulescu <ionut@moisil.cs.columbia.edu>]

On Tue, 22 May 2001 20:10:41 +0100 (BST), Alan Cox <alan@lxorguk.ukuu.org.uk> wrote:

> Before you give up on the xircom thing, try the -ac kernel and set the box
> up to use xircom_cb not xircom_tulip_cb
> 
> That might help a lot

It doesn't, it still performs poorly with any of the three available
drivers -- xircom_cb, xircom_tulip_cb, and tulip_cb (from the pcmcia package):

* Rx gets only about 1.8Mbit/s on a 100Base-TX network with any of the three
* Tx gets 80+Mb/s with xircom_tulip_cb and tulip_cb, and less than 30Mb/s
  with xircom_cb.

And no, promisc mode played no role in this experiment, because my test
network is switched and otherwise very quiet.

Windows drivers handle both Rx and Tx at full speed.

I have this feeling that we're handling the card in some (tulip) compat
mode, which severely cripples performance. It's hard to tell, without
docs...

Ion

-- 
  It is better to keep your mouth shut and be thought a fool,
            than to open it and remove all doubt.