Compilation Guide

Pitzer Compilers

The Skylake processors that make up the original Pitzer cluster and the Cascade Lake processors in its expansion support the AVX512 instruction set, but you must set the correct compiler flags to take advantage of it. AVX512 has the potential to speed up your code by a factor of 8 or more, depending on the compiler and options you would otherwise use.

With the Intel compilers, use -xHost and -O2 or higher. With the gnu compilers, use -march=native and -O3. The PGI compilers by default use the highest available instruction set, so no additional flags are necessary.

This advice assumes that you are building and running your code on Pitzer. The executables will not be portable.  Of course, any highly optimized builds, such as those employing the options above, should be thoroughly validated for correctness.

Owens Compilers

The Haswell and Broadwell processors that make up Owens support the Advanced Vector Extensions (AVX2) instruction set, but you must set the correct compiler flags to take advantage of it. AVX2 has the potential to speed up your code by a factor of 4 or more, depending on the compiler and options you would otherwise use.

With the Intel compilers, use -xHost and -O2 or higher. With the gnu compilers, use -march=native and -O3. The PGI compilers by default use the highest available instruction set, so no additional flags are necessary.

This advice assumes that you are building and running your code on Owens. The executables will not be portable. Of course, any highly optimized builds, such as those employing the options above, should be thoroughly validated for correctness.

Further Reading:

Intel Compiler Page

PGI Compiler Page

GNU Complier Page