DMA Performance

[austinsteamboat]

Hi, I just found your project and was curious if you've done any performance benchmarking of your driver for data transfer rates between CPU/FPGA? I've been working with the zynq-xdma driver from bmartini and while it works fairly well, it doesn't support scatter/gather so I was curious if that really improves performance or not.
Thanks,
-Austin

[guruofquality]

I have benchmarked it a long time ago and I really don't remember. But its all relative to what you are comparing to. The C driver is virtually out of the way, and it really comes down to what the application is doing with the buffer. Because the driver is doing nothing other than checking flags and bumping a scatter/gather pointer, seen here with the wait/acquire/release. And the actual transfers take place in the FPGA fabric where the AXI DMA block reads or writes from an HP memory interface port.