-  The size of the memory footprint.
+  The size of the memory footprint in megabytes (MB) for source and destination.

I prefer not add "for source and destination", it makes sense without this, and maybe future test like fill don't have source buffer.

The current dma-perf application, makes use of memory in MegaBytes for combined buffer of source and destination. That is, if the total memory is 10MB

this is split into 5MB for source buffer and 5MB for destination buffer.

dma-fill option is not enabled or used in dma-test-perf yet. I would recommend, once the feature is added `both fill-pattern and mem_size will get added`.

As it is not available this is  not applicable. Hence I am do not agree `it makes sense without this` instead it is needed to be clear.

 ``buf_size``
-  The memory size of a single operation.
+  The memory size of a single operation in bytes (B).

 ``dma_ring_size``
   The DMA ring buffer size. Must be a power of two, and between ``64`` and ``4096``.

BTW: Could you please also modify the app/test-dma-perf/config.ini (which also missing this)

dma-perf documentation is updated with right message. Yes, I can understand end-user may also refer to the comments in `config.ini`.  So yes i can shared v2 with same message as v1

`memsize is combination of source and destination in MB`

Thanks