Intel ARCHITECTURE IA-32 - Manual (Page 360)

IA-32 Intel® Architecture Optimization
7-14
Tools for Creating Multithreaded Applications
Programming directly to a multithreading application programming
interface (API) is not the only method for creating multithreaded
applications. New tools such as the Intel
® Compiler have become
available with capabilities that make the challenge of creating
multithreaded application easier.
Two features available in the latest Intel Compilers are:
• generating multithreaded code using OpenMP* directives 4
• generating multithreaded code automatically from unmodified
high-level code
5
Programming with OpenMP Directives. OpenMP provides a
standardized, non-proprietary, portable set of Fortran and C++ compiler
directives supporting shared memory parallelism in applications.
OpenMP supports directive-based processing. This uses special
preprocessors or modified compilers to interpret parallelism expressed
in Fortran comments or C/C++ pragmas. Benefits of directive-based
processing include:
• The original source can be compiled unmodified.
• It is possible to make incremental code changes. This preserves
algorithms in the original code and enables rapid debugging.
• Incremental code changes help programmers maintain serial
consistency. When the code is run on one processor, it gives the
same result as the unmodified source code.
• Offering directives to fine tune thread scheduling imbalance.
• Intel’s implementation of OpenMP runtime can add minimal
threading overhead relative to hand-coded multi-threading.
4. Intel Compiler 5.0 and later supports OpenMP directives. Visit
http://developer.intel.com/software/products for details.
5. Intel Compiler 6.0 supports auto-parallelization.