Parallel programming models provide perspectives from which
you can write—or adapt—code to run on a high-end
HP system. You can perform both shared-memory programming and message-passing
programming on an SMP. This book focuses on using the shared-memory
paradigm, but includes reference material and pointers to other
manuals about message passing.
The message-passing paradigm |
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HP has implemented a version of the message-passing interface
(MPI) standard known as HP MPI. This implementation is
finely tuned for HP technical servers.
In message-passing, a parallel application consists of a number
of processes that run concurrently. Each process has its own local
memory. It communicates with other processes by sending and receiving
messages. When data is passed in a message, both processes must
work to transfer the data from the local memory of one to the local
memory of the other.
Under the message-passing paradigm, functions allow you to
explicitly spawn parallel processes, communicate data among them,
and coordinate their activities. Unlike the previous model, there
is no shared-memory. Each process has its own private 16-terabyte
(Tbyte) address space, and any data that must be shared must be
explicitly passed between processes. Figure 1-2 “Message-passing programming model” shows a layout of the message-passing
paradigm.
Support of message passing allows programs written under this
paradigm for distributed memory to be easily ported to HP servers.
Programs that require more per-process memory than possible using
shared-memory benefit from the manually-tuned message-passing style.
For more information about HP MPI, see the HP MPI
User's Guide and the MPI Reference.
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