Possible values for type are: type = none (default) Does not bind OpenMP threads to particular thread contexts however, if the operating system supports affinity, the compiler still uses the OpenMP thread affinity interface to determine machine topology. Recommendation: Use Intel compiler versions 11.1 and later, as some of the affinity methods described below are not supported in earlier versions. Descriptions of all of the possible arguments ( type, modifier, permute, and offset) can be found in man ifort. Syntax -par-affinity= Possible Values for typeįor both of the recommended approaches, the only required argument is type, which indicates the type of thread affinity to use.

Note: Starting with comp-intel/2015.0.090, -openmp is deprecated and has been replaced with -qopenmp. This option overrides the environment variable when both are specified. The use of -openmp or -parallel is required in order for this option to take effect. Starting with the Intel compiler version 11.1, thread affinity can be specified through the compiler option -par-affinity. Syntaxįor csh and tcsh: setenv KMP_AFFINITY įor sh, bash, and ksh: export KMP_AFFINITY= Using the Compiler Flag -par-affinity Compiler Option The thread affinity interface is controlled using the KMP_AFFINITY environment variable. Using the KMP_AFFINITY Environment Variable We recommend two approaches for using the Intel OpenMP thread affinity capability. Depending on the system topology, application, and operating system, thread affinity can have a dramatic effect on code performance. The Intel compiler's OpenMP runtime library has the ability to bind OpenMP threads to physical processing units.

UPDATE IN PROGRESS: This article is being updated to support Skylake and Cascade Lake.

Intel c compiler flag list -c++