Intel Compilers¶
Introduction¶
Intel compilers are compilers for Intel processor-based systems, available for Microsoft Windows, Linux, and macOS operating systems.
Installed Versions¶
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
Warn
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
Read more here.