Subject: Re: atrocious tx performance of gigabit cardbus re(4)
To: None <>
From: David Young <>
List: tech-net
Date: 09/24/2007 11:35:50
On Mon, Sep 24, 2007 at 11:24:01AM -0500, Jonathan A. Kollasch wrote:
> Hi,
> I've got a Netgear GA511 (Gigabit CardBus re(4)). I recently got
> my first real gigabit peer (other than the gigabit ports on
> my 10/100+1000 switch) anyway, when I have the nfe(4) send
> a TCP stream at the re(4), I can get a reasonable (for some
> acceptable value thereof) 30 Mbytes/s. However, when I send
> from the re(4) to the nfe(4) I can only get 4Mbytes/s.
> From 100Mbps sources on the same switch I can get full
> Fast Ethernet performance to the nfe(4), so it's not
> that end's problem.
> Tests were performed using `nc6 -x` and progress(1).
> The cbb(4)s I'm using are TI, a product 0x8031 rev 0x0 and 
> a product 0x8039 rev 0x00 on NetBSD/i386 laptops running
> 4.0 BETA2 and 4.99.22.
> ISTR dyoung@ had performance problems with TI CardBus bridges
> before, but I'm not sure if those issues are also effecting
> me.

Hi Jonathan,

I have some patches that may help.  The problem is that NetBSD does not
enable read bursts on the PCI side of the bridge, so the bridge does
single-cycle transactions on the NIC's behalf.  What does dmesg say
about your cbb(4) ?


David Young             OJC Technologies      Urbana, IL * (217) 278-3933 ext 24