I/OAT configuration ?

Hi,
I am trying to use I/OAT on one of the newer woodcrest boxes.
But not sure if things are configured properly since there
seems to be no change in performance with I/OAT enabled
or disabled.
Following are the steps followed.
1. MSI (CONFIG_PCI_MSI) is enabled in kernel(2.6.16.21).
2. In kernel DMA configuration, following are enabled.
     Support for DMA Engines
     Network: TCP receive copy offload
     Test DMA Client
     Intel I/OAT DMA support
3. I manually load the ioatdma driver (modprobe ioatdma)

As per some documentation I read, when step #3 is performed
successfully, directories dma0chanX is supposed to be created
under /sys/class/dma but in my case, this directory stays
empty. I don't see any messages in /var/log/messages.
Any idea what is missing ?

Thanks,
Ravi