Sorry, this was poorly worded. All I meant was that in this example, we're
implementing the put/get windows with real shared memory pages and so we have
to be careful. Let's say we had a 16KB window and four MPI processes. If the
MPI implementation had only allocated a single page of shared memory for them,
we would get different behavior than what we wanted because any data that was
written into the window of any one process would also appear in the windows of
every other process. So, we instead allocate four shared pages and partition
them up between the four processes. By writing into the window of one process,
we are still causing changes that are visible in the address spaces of the
other processes but these changes are hidden by MPI.
-- Eric Salo Silicon Graphics Inc. "Do you know what the (415)933-2998 2011 N. Shoreline Blvd, 7L-802 last Xon said, just firstname.lastname@example.org Mountain View, CA 94043-1389 before he died?"