• discussions, visit: #system-programming on the PA&A Discord
• email discussion list - sign up @ sourceforge.net [archive]
  (*NOTE: I am working on email deliverability issues for gmail users, maybe other "free" email sites!)

• The OpenMP Common Core: A hands on exploration (3.5 hrs - Tim Mattson, Intel, 2019)
• Using OpenMP in Perl (2hrs - Houston PM, May 2021)
• Introduction to OpenMP for Perl Programmers (50m - TPRC 2022)
• State of the Art: Perl and Multithreading via OpenMP (50m - TPRC 2022)
• Intermediate OpenMP for Perl Programmers (50m - TPRC 2024)

• OpenMP - metapackage (includes following 2 modules w/lagniappe)
• OpenMP::Simple - helper C macros and runtime functions
• OpenMP::Environment - for managing variables in %ENV important to the OpenMP runtime

cpanm OpenMP # installs all of the above modules

Create this Perl file and execute on *nix using a perl built using gcc:

#!/usr/bin/env perluse strict;
use warnings;
use OpenMP;
use Inline (
C=>'DATA',
with=>qw/OpenMP::Simple/,
);
my$omp = OpenMP->new;
formy$want_num_threads ( 1 .. 8 ) {
$omp->env->omp_num_threads($want_num_threads);
$omp->env->assert_omp_environment; # (optional) validates %ENV# call parallelized C functionmy$got_num_threads = _check_num_threads();
printf"%0d threads spawned in ".
"the OpenMP runtime, expecting %0d\n",
$got_num_threads, $want_num_threads;
}
__DATA____C__/* C function parallelized with OpenMP */int _check_num_threads() { int ret = 0; PerlOMP_GETENV_BASIC #pragma omp parallel { #pragma omp single ret = omp_get_num_threads(); } return ret;}__END__

Expected Output:

1 threads spawned in the OpenMP runtime, expecting 1
2 threads spawned in the OpenMP runtime, expecting 2
3 threads spawned in the OpenMP runtime, expecting 3
4 threads spawned in the OpenMP runtime, expecting 4
5 threads spawned in the OpenMP runtime, expecting 5
6 threads spawned in the OpenMP runtime, expecting 6
7 threads spawned in the OpenMP runtime, expecting 7
8 threads spawned in the OpenMP runtime, expecting 8

That's up to you. Please share!

• #pragma omp parallel
• int omp_get_thread_num()
• int omp_get_num_threads()
• export OMP_NUM_THREADS=N
• #pragma omp barrier
• #pragma omp critical
• #pragma omp for
• #pragma omp parallel for
• reduction(op:list)
• schedule(dynamic[,chunk])
• shcedule(static,[,chunk])
• private(list), firstprivate(list), shared(list)
• nowait
• #pragma omp single
• #pragma omp task
• #pragma omp taskwait

See more below under "Videos."

• PDF The OpenMP Common Core: A journey back to the roots of OpenMP (Mattson, 2019) code
• PDF A Guide To OpenMP (Estrade, 2011)

• Amazon: The OpenMP Common Core: Making OpenMP Simple Again (Scientific and Engineering Computation) (ISBN: 0262538865)

• How Popular is OpenMP? (2023) - Spoiler it is VERY popular!

Highlighted slides fropm this video speak of the most popular OpenMP constructs; the red boxes are items in the first edition of Common Core, the items in green are identified by Mattson candiates for an updated version of the book since they have proven emiracally to be popular. The items in the first edition were a good guess: