GOMP_CPU_AFFINITY="0 3 1-2 4-15:2"will bind the initial thread to CPU 0, the second to CPU 3, the third to CPU 1, the fourth to CPU 2, the fifth to CPU 4, the sixth through tenth to CPUs 6, 8, 10, 12, and 14 respectively and then start assigning back from the beginning of the list.
GOMP_CPU_AFFINITY=0binds all threads to CPU 0.
There is no libgomp library routine to determine whether a CPU affinity
specification is in effect. As a workaround, language-specific library
getenv in C or
Fortran, may be used to query the setting of the
environment variable. A defined CPU affinity on startup cannot be changed
or disabled during the runtime of the application.
If both GOMP_CPU_AFFINITY and OMP_PROC_BIND are set,
OMP_PROC_BIND has a higher precedence. If neither has been set and
OMP_PROC_BIND is unset, or when OMP_PROC_BIND is set to
FALSE, the host system will handle the assignment of threads to CPUs.