Your observations are correct. If the payload is non-contiguous, then RDMA is not used. The data has to be copied first into an intermediate buffer and then sent. This has not changed in later version of Open MPI.
Rolf >-----Original Message----- >From: devel-boun...@open-mpi.org [mailto:devel-boun...@open-mpi.org] >On Behalf Of Sebastian Rinke >Sent: Wednesday, January 04, 2012 10:01 AM >To: Open MPI Developers >Subject: [OMPI devel] RDMA with non-contiguous payload > >Dear all, > >Playing around with GPUDirect v1 and Infiniband I noticed that once the >payload is non-contiguous no RDMA is used at all. >Can anybody confirm this? > >I'm using Open MPI 1.4.3. If the above is true, has this behavior changed with >later versions of Open MPI? > >Thanks a lot. > >Best, >Sebastian >_______________________________________________ >devel mailing list >de...@open-mpi.org >http://www.open-mpi.org/mailman/listinfo.cgi/devel ----------------------------------------------------------------------------------- This email message is for the sole use of the intended recipient(s) and may contain confidential information. Any unauthorized review, use, disclosure or distribution is prohibited. If you are not the intended recipient, please contact the sender by reply email and destroy all copies of the original message. -----------------------------------------------------------------------------------
