DMA on simultaneous AI & AO ?

Hi,

I'm trying to improve the streaming performance for simultaneous AI and
AO, for a NI-PCI-6071e Nat Inst E-Series card.

Doing either AI or AO on it's own, I can comfortably obtain streaming
rates at the card specs (1.2MS/s and 0.9MS/s for AI and AO
respectively).     (...& all from python ... how cool is that!)

However, if I try to do simultaneous AI & AO, the best I can get is
about 200kS/s. I'm sure this card support >1 DMA channels. Is this a
limitation of the ni_pcimio driver, or is there something I can do to
improve things?

On a different subject, does the linux kernel version make any
difference to comedi performance (e.g. does stuff  like kernel
preemption provide any benefits?). Emprically, I can see any difference
but I though I'd ask.

cheers,
Bryan
 

-- 
Bryan Cole
Teraview Ltd., 302-304 Cambridge Science Park, Milton Road, Cambridge CB4 0WG, United Kingdom.
tel: +44 (1223) 435380 / 435386 (direct-dial) fax: +44 (1223) 435382

Received on 2004-04-29Z18:33:13