diff --git a/docs.it4i/software/intel/intel-suite/intel-compilers.md b/docs.it4i/software/intel/intel-suite/intel-compilers.md index e883a251bc185256666894ed1a33f883287be693..6993a9b7cd4151820a25daf4c2009ab0f994ccbc 100644 --- a/docs.it4i/software/intel/intel-suite/intel-compilers.md +++ b/docs.it4i/software/intel/intel-suite/intel-compilers.md @@ -1,6 +1,6 @@ # Intel Compilers -The Intel compilers in multiple versions are available via the intel module. The compilers include the icc C and C++ compiler and the ifort Fortran 77/90/95 compiler. +The Intel compilers in multiple versions are available via the `intel` module. The compilers include the icc C and C++ compiler and the ifort Fortran 77/90/95 compiler. ```console $ ml intel @@ -17,9 +17,9 @@ $ icc -ipo -O3 -xCORE-AVX2 -qopt-report1 -qopt-report-phase=vec myprog.c mysub $ ifort -ipo -O3 -xCORE-AVX2 -qopt-report1 -qopt-report-phase=vec myprog.f mysubroutines.f -o myprog.x ``` -In this example, we compile the program enabling interprocedural optimizations between source files (-ipo), aggressive loop optimizations (-O3), and vectorization (-xCORE-AVX2). +In this example, we compile the program enabling interprocedural optimizations between source files (`-ipo`), aggressive loop optimizations (`-O3`), and vectorization (`-xCORE-AVX2`). -The compiler recognizes the omp, simd, vector, and ivdep pragmas for OpenMP parallelization and AVX2 vectorization. Enable the OpenMP parallelization by the **-openmp** compiler switch. +The compiler recognizes the omp, simd, vector, and ivdep pragmas for OpenMP parallelization and AVX2 vectorization. Enable the OpenMP parallelization by the `-openmp` compiler switch. ```console $ icc -ipo -O3 -xCORE-AVX2 -qopt-report1 -qopt-report-phase=vec -openmp myprog.c mysubroutines.c -o myprog.x @@ -32,7 +32,7 @@ Read more [here][a]. Anselm nodes are currently equipped with the Sandy Bridge CPUs, while Salomon compute nodes are equipped with the Haswell-based architecture. The UV1 SMP compute server has Ivy Bridge CPUs, which are equivalent to Sandy Bridge (only smaller manufacturing technology). The new processors are backward compatible with the Sandy Bridge nodes, so all programs that run on the Sandy Bridge processors should also run on the new Haswell nodes. To get the optimal performance out of the Haswell processors, a program should make use of the special AVX2 instructions for this processor. This can be done by recompiling codes with the compiler flags designated to invoke these instructions. For the Intel compiler suite, there are two options: -* Using compiler flag (both for Fortran and C): **-xCORE-AVX2**. This will create a binary with AVX2 instructions, specifically for the Haswell processors. Note that the executable will not run on Sandy Bridge/Ivy Bridge nodes. -* Using compiler flags (both for Fortran and C): **-xAVX -axCORE-AVX2**. This will generate multiple, feature specific auto-dispatch code paths for IntelĀ® processors, if there is a performance benefit. Therefore, this binary will run both on Sandy Bridge/Ivy Bridge and Haswell processors. During runtime, it will be decided which path to follow, dependent on which processor you are running on. In general this will result in larger binaries. +* Using compiler flag (both for Fortran and C): `-xCORE-AVX2`. This will create a binary with AVX2 instructions, specifically for the Haswell processors. Note that the executable will not run on Sandy Bridge/Ivy Bridge nodes. +* Using compiler flags (both for Fortran and C): `-xAVX -axCORE-AVX2`. This will generate multiple, feature specific auto-dispatch code paths for IntelĀ® processors, if there is a performance benefit. Therefore, this binary will run both on Sandy Bridge/Ivy Bridge and Haswell processors. During runtime, it will be decided which path to follow, dependent on which processor you are running on. In general, this will result in larger binaries. [a]: https://software.intel.com/en-us/intel-cplusplus-compiler-16.0-user-and-reference-guide