Registered memory in MPICH over GM

I have written a goodly amount of code using GM.  I am now about to use
MPICH-GM because I want to compare the performance of it with my code
while uses GM.

I have the following question.  If you call MPI_Send or MPI_Receive, are
the respective buffers copied into DMA-able memory with
gm_register_memory or is it assumed that the buffers are already
gm_registered?

William K. Allard
Professor of Mathematics
Box 90320
Durham, NC 27708-0320
(919) 660-2861 Fax:(919) 660-2864