Intel Compilers¶

Introduction¶

Intel compilers are compilers for Intel processor-based systems, available for Microsoft Windows, Linux, and macOS operating systems.

Installed Versions¶

New Compilers in intel/2023a Module

An intel/2023a module has been installed on the Karolina and Barbora clusters. This module contains new compilers icx, icpx, and ifx.
See the porting guides for ICC Users to DPCPP or ICX or for Intel® Fortran Compiler.

Intel compilers are available in multiple versions via the intel module. The compilers include the icc C and C++ compiler and the ifort Fortran 77/90/95 compiler.

For the current list of installed versions, use:

$ ml av intel/

$ ml intel/2020b
$ icc -v
icc version 19.1.3.304 (gcc version 10.2.0 compatibility)
$ ifort -v
ifort version 19.1.3.304

Instructions Vectorization¶

Intel compilers provide vectorization of the code via the AVX-2/AVX-512 instructions and support threading parallelization via OpenMP.

For maximum performance on the Barbora cluster compute nodes, compile your programs using the AVX-512 instructions, with reporting where the vectorization was used. We recommend the following compilation options for high performance.

Info

Barbora non-accelerated nodes support AVX-512 instructions (cn1-cn192).

$ icc -ipo -O3 -xCORE-AVX512 -qopt-report1 -qopt-report-phase=vec myprog.c mysubroutines.c -o myprog.x

In this example, we compile the program enabling interprocedural optimizations between source files (-ipo), aggressive loop optimizations (-O3), and vectorization (-xCORE-AVX512).

For maximum performance on the Barbora GPU nodes or Karolina cluster compute nodes, compile your programs using the AVX-2 instructions, with reporting where the vectorization was used. We recommend the following compilation options for high performance.

$ icc -ipo -O3 -xCORE-AVX2 -qopt-report1 -qopt-report-phase=vec myprog.c mysubroutines.c -o myprog.x

Warning

Karolina cluster has AMD cpu, use compiler options -march=core-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.

$ icc -ipo -O3 -xCORE-AVX2 -qopt-report1 -qopt-report-phase=vec -openmp myprog.c mysubroutines.c -o myprog.x