Enables the parallelizer to generate multi-threaded code based on the OpenMP* directives.
IDE Equivalent
Windows: Language > Process OpenMP Directives
Linux: None
Mac OS X: None
Architectures
IA-32, Intel® 64 architectures
Syntax
Linux and Mac OS X: | -openmp |
Windows: | /Qopenmp |
Arguments
None
Default
OFF |
No OpenMP* multi-threaded code is generated by the compiler. |
Description
This option enables the parallelizer to generate multi-threaded code based on the OpenMP* directives. The code can be executed in parallel on both uniprocessor and multiprocessor systems.
If you use this option, multithreaded libraries are used, but option fpp is not automatically invoked.
This option sets option automatic.
This option works with any optimization level. Specifying no optimization (-O0 on Linux or /Od on Windows) helps to debug OpenMP applications.
Note
On Mac OS* X systems, when you enable OpenMP*, you must also set the DYLD_LIBRARY_PATH environment variable within Xcode or an error will be displayed.
Note
Options that use OpenMP* are available for both Intel® microprocessors and non-Intel microprocessors, but these options may perform additional optimizations on Intel® microprocessors than they perform on non-Intel microprocessors. The list of major, user-visible OpenMP constructs and features that may perform differently on Intel® microprocessors versus non-Intel microprocessors include: locks (internal and user visible), the SINGLE construct, barriers (explicit and implicit), parallel loop scheduling, reductions, memory allocation, thread affinity, and binding.
Optimization Notice |
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Intel® Compiler includes compiler options that optimize for instruction sets that are available in both Intel® and non-Intel microprocessors (for example SIMD instruction sets), but do not optimize equally for non-Intel microprocessors. In addition, certain compiler options for Intel® Compiler are reserved for Intel microprocessors. For a detailed description of these compiler options, including the instruction sets they implicate, please refer to "Intel® Compiler User and Reference Guides > Compiler Options". Many library routines that are part of Intel® Compiler are more highly optimized for Intel microprocessors than for other microprocessors. While the compilers and libraries in Intel® Compiler offer optimizations for both Intel and Intel-compatible microprocessors, depending on the options you select, your code and other factors, you likely will get extra performance on Intel microprocessors. While the paragraph above describes the basic optimization approach for Intel® Compiler, with respect to Intel's compilers and associated libraries as a whole, Intel® Compiler may or may not optimize to the same degree for non-Intel microprocessors for optimizations that are not unique to Intel microprocessors. These optimizations include Intel® Streaming SIMD Extensions 2 (Intel® SSE2), Intel® Streaming SIMD Extensions 3 (Intel® SSE3), and Supplemental Streaming SIMD Extensions 3 (Intel® SSSE3) instruction sets and other optimizations. Intel does not guarantee the availability, functionality, or effectiveness of any optimization on microprocessors not manufactured by Intel. Microprocessor-dependent optimizations in this product are intended for use with Intel microprocessors. Intel recommends that you evaluate other compilers to determine which best meet your requirements. |
Alternate Options
None