[vortex] TX_Optimizing for 905x

Donald Becker becker@scyld.com
Thu Nov 22 11:01:01 2001

On Thu, 22 Nov 2001, Markus Fraedrich wrote:

> I tried to figure out, if its possible to optimise the Datarate from
> the Host to NIC finally to the Ethernet Bus .In the 3c59x.c (10Oct00)
> its is mentioned that the ring_size_lenght is important for
> effeciency.

> But has annyone expierence with changing the  DnPriority/BurstTresh
> and TxStartThresh Registers.

Yes.  The default settings are good for general purpose use.
You should really understand the system implications, especially PCI
burst behavior, before changing them.

> Are they used annywhere in the driver?

No, they are settings used by the hardware to decide how to handle bus
mastering PCI bursts.

> And What about scheduled DPD for video streams.

I've experimented with the real-time transmit scheduling.  It's a very
spiffy feature, but you'll find that it's mostly pointless for PC-based
video.  You'll get better behavior from a simple greedy transmit algorithm.

> Im using the 905B (Cyclone)

You probably want the 'C' for real-time transmits.

Donald Becker				becker@scyld.com
Scyld Computing Corporation		http://www.scyld.com
410 Severn Ave. Suite 210		Second Generation Beowulf Clusters
Annapolis MD 21403			410-990-9993