Subject: Re: atrocious tx performance of gigabit cardbus re(4)
To: David Young <>
From: Jonathan A. Kollasch <>
List: tech-net
Date: 09/25/2007 14:22:23
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On Mon, Sep 24, 2007 at 11:35:50AM -0500, David Young wrote:
> On Mon, Sep 24, 2007 at 11:24:01AM -0500, Jonathan A. Kollasch wrote:
> > Hi,
> >=20
> > I've got a Netgear GA511 (Gigabit CardBus re(4)). I recently got
> > .......
> > 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) ?

Nothing unusual AFAICT:

The 4.99.22 on a Toshiba A135-S4527:

cbb0 at pci4 dev 4 function 0: Texas Instruments product 0x8039 (rev. 0x00)
=2E.. (other functions of the chip: 1394, media card reader, sdhci)
cbb0: interrupting at ioapic0 pin 16 (irq 255)
cardslot0 at cbb0 slot 0 flags 0
cardbus0 at cardslot0: bus 5
pcmcia0 at cardslot0

The other box (Compaq M2005US) is essentially the same,
but the product ID is recognized. ("PCI7x21/7x11 ...")

The actual chip is marked PCI7411 in the Compaq,
I've not opened the Toshiba.

<long pause>

I took the liberty of testing your patch from
(well, not the patch itself, just unconditionally setting the bits).
TX performance on the Compaq (1.3GHz Celeron Dothan) increased to
about 16Mbytes/s. RX increased some too.

	Jonathan Kollasch

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