[openib-general] basic IB doubt

[Sean Hefty]

john t wrote:
> I have a very basic doubt. Suppose Host A is doing RDMA write (say 8 
> MB) to Host B. When data is copied into Host B's local buffer, is it 
> guaranteed that data will be copied starting from the first location 
> (first buffer address) to the last location (last buffer address)? or it 
> could be in any order?

I don't believe that there is any ordering guarantee by the architecture. 
However, specific adapters may behave this way, and I've seen applications make 
use of this by polling the last memory byte for a completion, for example.

> Also does this tranfer involve DMA engine (residinng on HCAs) of both 
> the hosts or just one host?

If I'm understanding the question correctly, the DMA engine of both HCAs are used.

- Sean