8260 IDMA experience?

[Arto Vuori]

Allen Curtis wrote:
>
> Does anyone have experience with IDMA on the 8260? Are there any special
> considerations if you wanted to use the memory-to-memory copy function in
> place of a memcpy()? (kernel memory only at this time)

I have been using IDMA to transfer data between kernel memory and a
FPGA. I also did some testing with memory-to-memory transfers and i
didn't find them to be worth the trouble. Performance ain't that great.
You probably get more speed by copying with your CPU, though you might
avoid some cache trashing.

I did also notice that when i am doing memory-to-peripheral (or
vice-versa) transfers, IDMA corrupts simultaneous Ethernet traffic
unless IDMA is set to low-priority mode. Same might apply for
memory-to-memory transfers.

Arto

--
Arto Vuori
email: avuori at ssh.com
mobile:	+358 40 754 5223

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