OMP_AFFINITY_FORMAT – Set the format string used for affinity display ¶Sets the format string used when displaying OpenMP thread affinity information.
Special values are output using % followed by an optional size
specification and then either the single-character field type or its long
name enclosed in curly braces; using %% displays a literal percent.
The size specification consists of an optional 0. or . followed
by a positive integer, specifying the minimal width of the output. With
0. and numerical values, the output is padded with zeros on the left;
with ., the output is padded by spaces on the left; otherwise, the
output is padded by spaces on the right. If unset, the value is
“level %L thread %i affinity %A”.
Supported field types are:
| t | team_num | value returned by omp_get_team_num |
| T | num_teams | value returned by omp_get_num_teams |
| L | nesting_level | value returned by omp_get_level |
| n | thread_num | value returned by omp_get_thread_num |
| N | num_threads | value returned by omp_get_num_threads |
| a | ancestor_tnum | value returned by
omp_get_ancestor_thread_num(omp_get_level()-1) |
| H | host | name of the host that executes the thread |
| P | process_id | process identifier |
| i | native_thread_id | native thread identifier |
| A | thread_affinity | comma separated list of integer values or ranges, representing the processors on which a process might execute, subject to affinity mechanisms |
For instance, after setting
OMP_AFFINITY_FORMAT="%0.2a!%n!%.4L!%N;%.2t;%0.2T;%{team_num};%{num_teams};%A"
with either OMP_DISPLAY_AFFINITY being set or when calling
omp_display_affinity with NULL or an empty string, the program
might display the following:
00!0! 1!4; 0;01;0;1;0-11 00!3! 1!4; 0;01;0;1;0-11 00!2! 1!4; 0;01;0;1;0-11 00!1! 1!4; 0;01;0;1;0-11
OpenMP specification v5.0, Section 6.14