Re: [OMPI users] Does MPI_Bsend always use the buffer?
>This is an implementation details. You should avoid relying on such >things in a portable MPI applications. The safe assumption here is >that MPI_Bsend always copy the buffer, as described in the MPI standard. I'm fully aware of the MPI standard, and the program will be standard-compliant. However, since performance is somewhat important even in this emulated mode I want to understand what the OpenMPI implementation is likely to do. Pete
Re: [OMPI users] Does MPI_Bsend always use the buffer?
On Dec 11, 2007, at 10:33 AM, Gleb Natapov wrote: On Tue, Dec 11, 2007 at 10:27:32AM -0500, Bradley, Peter C. (MIS/ CFD) wrote: In OpenMPI, does MPI_Bsend always copy the message to the user- specified buffer, or will it avoid the copy in situations where it knows the send can complete? If the message size if smaller than eager limit Open MPI will not use user-specified buffer for it. This is an implementation details. You should avoid relying on such things in a portable MPI applications. The safe assumption here is that MPI_Bsend always copy the buffer, as described in the MPI standard. george. smime.p7s Description: S/MIME cryptographic signature
Re: [OMPI users] Does MPI_Bsend always use the buffer?
On Tue, Dec 11, 2007 at 10:27:32AM -0500, Bradley, Peter C. (MIS/CFD) wrote: > In OpenMPI, does MPI_Bsend always copy the message to the user-specified > buffer, or will it avoid the copy in situations where it knows the send can > complete? If the message size if smaller than eager limit Open MPI will not use user-specified buffer for it. -- Gleb.
