REQ: advice on tuning via-velocity parameters

I have a GBe Via Velocity NIC on an Abit AV8 motherboard, with
1GB DDR and a 3700+ CPU, running kernel 2.6.19. When I push a
lot of data via TCP-mounted NFS, I get a lot of these messages
in the system log and the machine is briefly slow to respond:

eth0: excessive work at interrupt.

I am guessing the system becomes slow when it is 'catching up'
with all the interrupts.

There are a lot of parameters associated with the via-velocity
driver. Is there a reference online detailing how to adjust
them, or a more general network-card kernel parameter tuning
FAQ?

I have txcsum_offload enabled.

rx_copybreak
Copy breakpoint for copy-only-tiny-frames (int)

int_works
Number of packets per interrupt services (array of int)

txcsum_offload
Enable transmit packet checksum offload (array of int)

IP_byte_align
Enable IP header dword aligned (array of int)

DMA_length
DMA length (array of int)

rx_thresh
Receive fifo threshold (array of int)

TxDescriptors
Number of transmit descriptors (array of int)
parm
RxDescriptors
Number of receive descriptors (array of int)


--
Brian Hall
http://pcisys.net/~brihall