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h2. Routines for Runtime Scheduling in OpenMP 3.0

In OpenMP 3.0, a new Internal Control Variable (ICV), called run-sched-var, has been introduced, and two new runtime routines to set/get the RUNTIME schedule have been added.

See the following related sections in the OpenMP specification:

Section 2.3 : run-sched-var internal control variable (ICV)
Section 3.2.11: omp_set_schedule runtime routine
Section 3.2.12: omp_get_schedule runtime routine

*Example (Fortran):*
{noformat}
include "omp_lib.h"
integer kind, modifier

call omp_set_dynamic(.false.)
call omp_set_num_threads(10)
print *, "Num threads =", omp_get_num_threads()
print *, "Max threads =", omp_get_max_threads()

call omp_set_schedule(omp_sched_static, 11)
call omp_get_schedule(kind, modifier)
print *, "Schedule: kind =", kind, "modifier =", modifier

call omp_set_schedule(omp_sched_dynamic, 12)
call omp_get_schedule(kind, modifier)
print *, "Schedule: kind =", kind, "modifier =", modifier

call omp_set_schedule(omp_sched_guided, 13)
call omp_get_schedule(kind, modifier)
print *, "Schedule: kind =", kind, "modifier =", modifier

call omp_set_schedule(omp_sched_auto, 14)
call omp_get_schedule(kind, modifier)
print *, "Schedule: kind =", kind, "modifier =", modifier

call omp_set_schedule(sunw_mp_sched_reserved, 1501)
call omp_get_schedule(kind, modifier)
print *, "Schedule: kind =", kind, "modifier =", modifier
end


% f90 -xopenmp -xO3 test.f
% a.out
Num threads = 1
Max threads = 10
Schedule: kind = 1 modifier = 11
Schedule: kind = 2 modifier = 12
Schedule: kind = 3 modifier = 13
Schedule: kind = 4 modifier = 0
Schedule: kind = 1 modifier = 0
{noformat}
*Example (C/C++):*
{noformat}
#include "omp.h"
#include <stdio.h>

int main()
{
int i, x;
omp_sched_t runtime_sched;
int runtime_chunk;

omp_set_dynamic(0);
omp_set_num_threads(4);

omp_get_schedule (&runtime_sched, &runtime_chunk);
printf ("runtime schedule = %d, chunk = %d\n", runtime_sched, runtime_chunk);

omp_set_schedule(omp_sched_auto, 10);
omp_get_schedule (&runtime_sched, &runtime_chunk);
printf ("runtime schedule = %d, chunk = %d\n", runtime_sched, runtime_chunk);

x = 0;

#pragma omp parallel private(runtime_sched, runtime_chunk)
{
if (omp_get_thread_num() == 0) {
omp_get_schedule (&runtime_sched, &runtime_chunk);
printf ("runtime schedule = %d, chunk = %d\n", runtime_sched, runtime_chunk);
}

#pragma omp barrier

if (omp_get_thread_num() > 0) {
omp_get_schedule (&runtime_sched, &runtime_chunk);
printf ("runtime schedule = %d, chunk = %d\n", runtime_sched, runtime_chunk);
}

#pragma omp barrier

#pragma omp for ordered schedule (runtime)
for (i = 0; i <= 10; i++)
{
#pragma omp atomic
x += 1;

#pragma omp ordered
{
omp_get_schedule (&runtime_sched, &runtime_chunk);
printf ("runtime schedule = %d, chunk = %d\n", runtime_sched, runtime_chunk);
}
}
}

omp_get_schedule (&runtime_sched, &runtime_chunk);
printf ("runtime schedule = %d, chunk = %d\n", runtime_sched, runtime_chunk);

omp_set_schedule(omp_sched_guided, 20);
omp_get_schedule (&runtime_sched, &runtime_chunk);
printf ("runtime schedule = %d, chunk = %d\n", runtime_sched, runtime_chunk);
}


% cc -xopenmp -xO3 test.c
% setenv OMP_SCHEDULE DYNAMIC,5
% a.out
runtime schedule = 2, chunk = 5
runtime schedule = 4, chunk = 0
runtime schedule = 4, chunk = 0
runtime schedule = 4, chunk = 0
runtime schedule = 4, chunk = 0
runtime schedule = 4, chunk = 0
runtime schedule = 4, chunk = 0
runtime schedule = 4, chunk = 0
runtime schedule = 4, chunk = 0
runtime schedule = 4, chunk = 0
runtime schedule = 4, chunk = 0
runtime schedule = 4, chunk = 0
runtime schedule = 4, chunk = 0
runtime schedule = 4, chunk = 0
runtime schedule = 4, chunk = 0
runtime schedule = 4, chunk = 0
runtime schedule = 4, chunk = 0
runtime schedule = 4, chunk = 0
runtime schedule = 3, chunk = 20
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{panel:title=OpenMP 3.0 Features in Express 7.08}
{children:page=Sun Studio OpenMP}
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