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program openmp_67
use omp_lib
implicit none
integer, parameter :: n = 10000
integer :: i, j
real :: static_time, dynamic_time, guided_time
double precision :: start_time
real :: a(n), b(n), c(n)
call omp_set_num_threads(4)
print *, "=== Schedule Comparison Test ==="
print *, "Comparing performance of different schedules"
print *, "Array size:", n, "Threads:", omp_get_max_threads()
! Initialize arrays
! Alternative: Initialize arrays with deterministic values
do i = 1, n
b(i) = real(i)
c(i) = real(n - i + 1)
end do
! Test STATIC
start_time = omp_get_wtime()
!$omp parallel do schedule(static)
do i = 1, n
a(i) = sqrt(b(i)) + log(abs(c(i)) + 1.0)
end do
!$omp end parallel do
static_time = omp_get_wtime() - start_time
! Test DYNAMIC
start_time = omp_get_wtime()
!$omp parallel do schedule(dynamic)
do i = 1, n
a(i) = sqrt(b(i)) + log(abs(c(i)) + 1.0)
end do
!$omp end parallel do
dynamic_time = omp_get_wtime() - start_time
! Test GUIDED
start_time = omp_get_wtime()
!$omp parallel do schedule(guided)
do i = 1, n
a(i) = sqrt(b(i)) + log(abs(c(i)) + 1.0)
end do
!$omp end parallel do
guided_time = omp_get_wtime() - start_time
! Print results
print '(A,F8.6,A)', "STATIC time: ", static_time, " seconds"
print '(A,F8.6,A)', "DYNAMIC time: ", dynamic_time, " seconds"
print '(A,F8.6,A)', "GUIDED time: ", guided_time, " seconds"
! Analysis
print *, ""
print *, "Analysis:"
! For uniform workload, static should be fastest
if (static_time < dynamic_time * 0.9 .and. static_time < guided_time * 0.9) then
print *, "✓ STATIC is fastest for uniform workload"
else if (dynamic_time < static_time * 0.9) then
print *, "! DYNAMIC is fastest"
else if (guided_time < static_time * 0.9) then
print *, "! GUIDED is fastest"
else
print *, "- All schedules perform similarly"
end if
! Test with non-uniform workload
print *, ""
print *, "Testing with non-uniform workload..."
! Make some iterations heavier
do i = 1, n
if (mod(i, 10) == 0) then
b(i) = b(i) * 1000.0 ! Make every 10th iteration heavier
end if
end do
! Test STATIC with non-uniform
start_time = omp_get_wtime()
!$omp parallel do schedule(static)
do i = 1, n
if (mod(i, 10) == 0) then
! Heavy computation
a(i) = 0.0
do j = 1, 100
a(i) = a(i) + sqrt(b(i)) + log(abs(c(i)) + 1.0)
end do
else
a(i) = sqrt(b(i)) + log(abs(c(i)) + 1.0)
end if
end do
!$omp end parallel do
static_time = omp_get_wtime() - start_time
! Test DYNAMIC with non-uniform
start_time = omp_get_wtime()
!$omp parallel do schedule(dynamic)
do i = 1, n
if (mod(i, 10) == 0) then
a(i) = 0.0
do j = 1, 100
a(i) = a(i) + sqrt(b(i)) + log(abs(c(i)) + 1.0)
end do
else
a(i) = sqrt(b(i)) + log(abs(c(i)) + 1.0)
end if
end do
!$omp end parallel do
dynamic_time = omp_get_wtime() - start_time
print *, ""
print *, "Non-uniform workload results:"
print '(A,F8.6,A)', "STATIC time: ", static_time, " seconds"
print '(A,F8.6,A)', "DYNAMIC time: ", dynamic_time, " seconds"
end program openmp_67
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