[dcmf] Question about DCMF Library from a new user

[Rajesh Nishtala]

Hi,
 I am porting GASNet, our portable runtime layer for the Berkeley UPC
compiler, to the BlueGene/P and i'm using DCMF as the lower level
messaging layer. I have some high level questions regarding the
library that will influence the design of our BlueGene/P port. The
main difference between our library and MPI is that we focus on
one-sided communication so my main questions are regarding these
issues.

+ When does the callback that gets registered with DCMF_Send() get
called? Does it get called after the data has been committed to the
memory on the remote node or does it simply imply that the data buffer
is safe to reuse on the local node?

+ I notice that when I do an nm on the dcmf libraries there is
DCMF_Put() function, however when i waded through the code a little
bit more I noticed that the function simply called an abort which to
me implies that it is not implemented. Is this why it doesn't show up
in the dcmf.h header files?

+ I have heard that the BlueGene/P supports RDMA operations. Are there
any special considerations for managing the memory registration (i.e.
memory pinning) to enable these operations or is this done
automatically under the covers?


Thanks in advance for any help!

Sincerely,
Rajesh Nishtala