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Using one of the HP language compilers—Fortran, C/C++,
or UPC (Unified Parallel C)— parallel software programs
are designed, created, and modified. Non-parallel
components | |
Serial optimizations of the non-parallel components of a program
are performed with the use of Fortran, C/C++, or UPC compiler switches.
Additional optimization can occur with the use of HP MLIB. Parallel
components | |
The parallel components of the program are implemented by
multi-threading and/or message passing techniques. UPC provides a simple shared memory model for parallel programming,
allowing data to be shared or distributed among a number of communicating
processors. This model allows easier coding of parallel applications
and maximum performance across shared memory, distributed memory,
and hybrid systems. HP Fortran and C/C++ compilers support the shared memory OpenMP
construct for creating multi-threads. Additionally, HP provides
a message passing library—HP MPI—which runs on all
HP platforms. Using these techniques, you can create program concurrency
where different parts of the program run in parallel, thereby minimizing
execution time. Debugging | |
During compilation, the program may encounter errors and require
debugging. Errors can be located using the HP WDB debugger or the
Etnus TotalView debugger. Both tools are designed to work with the
various compilers used to build the program. The HP WDB debugger is an HP-supported implementation of the
GDB debugger that supports debugging serial and Pthreaded programs.
It supports source-level debugging of object files written in HP
C, HP aC++, Fortran 90, and Fortran 77. HP’s implementation includes
many enhancements to GDB such as enabling/disabling threads, debugging
memory problems, and heap analysis. For more information, visit http://www.hp.com/go/wdb Tuning
and profiling | |
Once the program is debugged and working properly, it can
be instrumented to obtain performance profiles through the use of
HP Caliper. HP Caliper is a general-purpose performance analysis tool
for applications on Itanium-based HP-UX and Linux systems. HP Caliper
allows users to understand the performance of their program and
to identify ways to improve its run-time performance. It supports
Fortran, C/C++, and threads. Tuning and profiling will help achieve your goal of writing
a parallel program that scales with the number of processors in
the system on which it is running. For more information, visit http://www.hp.com/go/caliper |
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