RE: I/OAT configuration ?

From: Ravinandan Arakali

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 ?

Does a PCI device with vendor ID 8086 and device ID 1a38 show up in
lspci?  That's the embedded DMA engine in the MCH.  It's only in the
5000 series chipsets, and may require a BIOS setting to enable.  It
should show up as bus 0 device 8 (00:08.0).

- Chris