refactor(omp): move omp sendrecv to its own file

Author: Nanoseb

src/CMakeLists.txt

@@ -8,6 +8,7 @@ set(SRC
   omp/backend.f90
   omp/common.f90
   omp/kernels_dist.f90
+  omp/sendrecv.f90
 )
 set(CUDASRC
   cuda/backend.f90

src/omp/sendrecv.f90

@@ -0,0 +1,38 @@
+module m_omp_sendrecv
+   use mpi
+
+   use m_common, only: dp
+
+   implicit none
+
+contains
+
+   subroutine sendrecv_fields(f_recv_s, f_recv_e, f_send_s, f_send_e, &
+                              n_data, nproc, prev, next)
+      implicit none
+
+      real(dp), dimension(:, :, :), intent(out) :: f_recv_s, f_recv_e
+      real(dp), dimension(:, :, :), intent(in) :: f_send_s, f_send_e
+      integer, intent(in) :: n_data, nproc, prev, next
+
+      integer :: req(4), err(4), ierr, tag = 1234
+
+      if (nproc == 1) then
+         f_recv_s = f_send_e
+         f_recv_e = f_send_s
+      else
+         call MPI_Isend(f_send_s, n_data, MPI_DOUBLE_PRECISION, &
+                        prev, tag, MPI_COMM_WORLD, req(1), err(1))
+         call MPI_Irecv(f_recv_e, n_data, MPI_DOUBLE_PRECISION, &
+                        next, tag, MPI_COMM_WORLD, req(2), err(2))
+         call MPI_Isend(f_send_e, n_data, MPI_DOUBLE_PRECISION, &
+                        next, tag, MPI_COMM_WORLD, req(3), err(3))
+         call MPI_Irecv(f_recv_s, n_data, MPI_DOUBLE_PRECISION, &
+                        prev, tag, MPI_COMM_WORLD, req(4), err(4))
+
+         call MPI_Waitall(4, req, MPI_STATUSES_IGNORE, ierr)
+      end if
+
+   end subroutine sendrecv_fields
+
+end module m_omp_sendrecv

tests/omp/test_omp_tridiag.f90

@@ -6,6 +6,7 @@ program test_omp_tridiag
    use m_common, only: dp, pi
    use m_omp_common, only: SZ
    use m_omp_kernels_dist, only: der_univ_dist_omp, der_univ_subs_omp
+   use m_omp_sendrecv, only: sendrecv_fields
 
    use m_tdsops, only: tdsops_t, tdsops_init
 
@@ -297,28 +298,9 @@ subroutine run_kernel(n_iters, n_block, u, du, tdsops, n, &
          !$omp end parallel do
 
          ! halo exchange
-         if (nproc == 1) then
-            u_recv_s = u_send_e
-            u_recv_e = u_send_s
-         else
-            ! MPI send/recv for multi-rank simulations
-            call MPI_Isend(u_send_s, SZ*n_halo*n_block, &
-                           MPI_DOUBLE_PRECISION, pprev, tag1, MPI_COMM_WORLD, &
-                           mpireq(1), srerr(1))
-            call MPI_Irecv(u_recv_e, SZ*n_halo*n_block, &
-                           MPI_DOUBLE_PRECISION, pnext, tag1, MPI_COMM_WORLD, &
-                           mpireq(2), srerr(2))
-            call MPI_Isend(u_send_e, SZ*n_halo*n_block, &
-                           MPI_DOUBLE_PRECISION, pnext, tag2, MPI_COMM_WORLD, &
-                           mpireq(3), srerr(3))
-            call MPI_Irecv(u_recv_s, SZ*n_halo*n_block, &
-                           MPI_DOUBLE_PRECISION, pprev, tag2, MPI_COMM_WORLD, &
-                           mpireq(4), srerr(4))
-
-            call MPI_Waitall(4, mpireq, MPI_STATUSES_IGNORE, ierr)
-         end if
-
-
+         call sendrecv_fields(u_recv_s, u_recv_e, u_send_s, u_send_e, &
+                               SZ*n_halo*n_block, nproc, pprev, pnext)
+         
          !$omp parallel do
          do k = 1, n_block
             call der_univ_dist_omp( &