Open MPI logo

Open MPI Development Mailing List Archives

  |   Home   |   Support   |   FAQ   |   all Development mailing list

Subject: Re: [OMPI devel] RFC: new btl descriptor flags
From: Nathan Hjelm (hjelmn_at_[hidden])
Date: 2011-11-29 15:52:07

On Tue, 29 Nov 2011, George Bosilca wrote:

> These two functions target at defining a memory layout (contiguous or not) that can be target for a one-sided communication. I don't see why there is a need to know what type of communication that will be … What is so different in the xpmem that requires the memory to be prepared based on the operations that will follow?

This would be for the ugni btl, not xpmem. Some uGNI rdma operations do not require registration (FMA put). If we know the type of operation at prepare_src we can avoid registering memory in these cases.

> Moreover, the prepare_src is used outside the context of one-sided, in the send protocol. How do you plan to address send operations?

Send operations can be detected by neither MCA_BTL_DES_PUT or MCA_BTL_DES_GET being set or a non-zero reserve value (which some btls already use).