Subject: Re: atrocious tx performance of gigabit cardbus re(4)
To: Steven M. Bellovin <>
From: None <>
List: tech-net
Date: 09/25/2007 13:00:23
In message <>,
"Steven M. Bellovin" writes:

>On Tue, 25 Sep 2007 14:32:32 -0500
>David Young <> wrote:
>> It may be possible to get even higher performance by tweaking
>> parameters both on the bridge and on the NIC.  For example, the
>> latency timer on the primary (PCI) bus may be rather small.  On the
>> NIC, both the PCI latency timer and the DMA burst parameters (highly
>> NIC-specific) may be too small.
>I'm trying to find my notes, but if memory serves correctly I had
>serious performance issues with a PCI re(4) on a gigE it.

[The driver and cardbus frontend are quite likely poorly
tuned or untuned.

If dim memory serves, I split the re driver and added the cardbus
frontend onne weekend, while the dongle on my old 3com cardbus card
was dying. The replacement card I had picked up at Fry's was one of
the first re(4) cardbus cards to hit the market. I did no more than
get the darn thing to work at 100Mbit and get the link LEDs working
and transmit of *some* packets working at gigabit speed.