(1) On P440-P441 it say that "RMA operations on win started by a process after the fence call returns will access their target window only after MPI_WIN_FENCE has been called by the target process". This requires MPI_WIN_FENCE that starts an epoch to act as an barrier.

It only says "RMA operations on win started by a process after the fence call returns will access their target window only after MPI_WIN_FENCE has been called by the target process". NOT "This requires MPI_WIN_FENCE that starts an epoch to act as an barrier." Why does the fence have to act as a barrier. The handshake could be done when first RMA operation is called after the fence. Rajeev On Feb 25, 2014, at 8:41 PM, "Zhao, Xin" <[email protected]> wrote:

Hi all,

There is an inconsistency of MPI_WIN_FENCE semantic in MPI 3.0 Standard that makes me confused:

(1) On P440-P441 it say that "RMA operations on win started by a process after the fence call returns will access their target window only after MPI_WIN_FENCE has been called by the target process". This requires MPI_WIN_FENCE that starts an epoch to act as an barrier.

(2) However, (1) contradict with the word at end of P441: "a call to MPI_WIN_FENCE that is known not to end any epoch (in particular a call with assert equal to MPI_MODE_NOPRECEDE) does not necessarily act as a barrier".

Should the word of (1) add: "when MPI_MODE_NOPRECEDE is not given"?

Thanks,

Xin

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