fix issue with mpi-serial io

Author: jedwards4b

src/share/util/shr_pio_mod.F90

@@ -506,12 +506,17 @@ subroutine shr_pio_read_default_namelist(nlfilename, Comm, pio_stride, pio_root,
     call shr_mpi_bcast(pio_buffer_size_limit, Comm)
     call shr_mpi_bcast(pio_async_interface, Comm)
     call shr_mpi_bcast(pio_rearranger, Comm)
+    if (npes == 1) then
+       pio_rearr_comm_max_pend_req_comp2io = 0
+       pio_rearr_comm_max_pend_req_io2comp = 0
+    endif
+
 
-     call shr_pio_rearr_opts_set(Comm, pio_rearr_comm_type, pio_rearr_comm_fcd, &
-           pio_rearr_comm_max_pend_req_comp2io, pio_rearr_comm_enable_hs_comp2io, &
-           pio_rearr_comm_enable_isend_comp2io, &
-           pio_rearr_comm_max_pend_req_io2comp, pio_rearr_comm_enable_hs_io2comp, &
-           pio_rearr_comm_enable_isend_io2comp, pio_numiotasks)
+    call shr_pio_rearr_opts_set(Comm, pio_rearr_comm_type, pio_rearr_comm_fcd, &
+         pio_rearr_comm_max_pend_req_comp2io, pio_rearr_comm_enable_hs_comp2io, &
+         pio_rearr_comm_enable_isend_comp2io, &
+         pio_rearr_comm_max_pend_req_io2comp, pio_rearr_comm_enable_hs_io2comp, &
+         pio_rearr_comm_enable_isend_io2comp, pio_numiotasks)
 
   end subroutine shr_pio_read_default_namelist
 
@@ -807,7 +812,7 @@ subroutine shr_pio_rearr_opts_set(comm, pio_rearr_comm_type, pio_rearr_comm_fcd,
       end select
 
       ! buf(3) = max_pend_req_comp2io
-      if((pio_rearr_comm_max_pend_req_comp2io <= 0) .and. &
+      if((pio_rearr_comm_max_pend_req_comp2io < 0) .and. &
           (pio_rearr_comm_max_pend_req_comp2io /= PIO_REARR_COMM_UNLIMITED_PEND_REQ)) then
 
         ! Small multiple of pio_numiotasks has proven to perform
@@ -839,7 +844,7 @@ subroutine shr_pio_rearr_opts_set(comm, pio_rearr_comm_type, pio_rearr_comm_fcd,
       end if
 
       ! buf(6) = max_pend_req_io2comp
-      if((pio_rearr_comm_max_pend_req_io2comp <= 0) .and. &
+      if((pio_rearr_comm_max_pend_req_io2comp < 0) .and. &
           (pio_rearr_comm_max_pend_req_io2comp /= PIO_REARR_COMM_UNLIMITED_PEND_REQ)) then
         write(shr_log_unit, *) "Invalid PIO rearranger comm max pend req (io2comp), ", pio_rearr_comm_max_pend_req_io2comp
         write(shr_log_unit, *) "Resetting PIO rearranger comm max pend req (io2comp) to ", PIO_REARR_COMM_DEF_MAX_PEND_REQ