Reduce the memory usage that is important for ne1024 simulation

.gitmodules

@@ -92,7 +92,7 @@ fxDONOTUSEurl = https://github.com/ESCOMP/CMEPS.git
 [submodule "cdeps"]
 path = components/cdeps
 url = https://github.com/ESCOMP/CDEPS.git
-fxtag = cdeps1.0.96
+fxtag = cdeps1.0.100
 fxrequired = ToplevelRequired
 # Standard Fork to compare to with "git fleximod test" to ensure personal forks aren't committed
 fxDONOTUSEurl = https://github.com/ESCOMP/CDEPS.git

src/biogeophys/UrbanParamsType.F90

@@ -425,7 +425,10 @@ subroutine UrbanInput(begg, endg, mode)
          if (masterproc) write(iulog,*)'PCT_URBAN is not multi-density, nlevurb set to 0'
        end if
 
-       if ( nlevurb == 0 ) return
+       if ( nlevurb == 0 ) then
+          call ncd_pio_closefile(ncid)
+          return
+       end if
 
        ! Allocate dynamic memory
        allocate(urbinp%canyon_hwr(begg:endg, numurbl), &

src/cpl/share_esmf/clm_shmem_mod.F90

@@ -0,0 +1,228 @@
+module clm_shmem_mod
+  !-----------------------------------------------------------------------------
+  ! Per-node MPI-3 shared-memory helper for large arrays that would otherwise be
+  ! replicated identically on every MPI rank.  One physical copy is allocated per
+  ! shared-memory node and mapped into every rank on that node, freeing
+  ! (ranks_per_node - 1) copies per node.
+  !
+  ! Ported from CAM's cam_shmem_mod (src/utils/cam_shmem_mod.F90) and specialized
+  ! for the CTSM decomposition setup: it provides a default-integer rank-1
+  ! allocator (the CAM module only has real r4/r8 2d-5d wrappers) plus a
+  ! node-leader sum-reduce that builds a globally-summed array in a node-shared
+  ! buffer without every rank holding its own global-sized copy.
+  !
+  ! Usage (collective over the land communicator mpicom):
+  !   call clm_shmem_alloc_i4_1d(ptr, win, n)        ! all ranks
+  !   if (clm_shmem_is_leader()) ptr(:) = 0          ! leader owns the storage
+  !   call clm_shmem_fence(win)                       ! publish the zeros
+  !   <each rank stores into its disjoint indices of ptr>
+  !   call clm_shmem_leader_allreduce_sum_i4(ptr,win,n) ! fence; sum across nodes; fence
+  !   <all ranks may now read ptr for the rest of its lifetime>
+  !   call clm_shmem_free(ptr, win)                   ! collective over the node comm
+  !
+  ! The MPI-3 shared-memory path is used for real MPI builds.  mpi-serial does not
+  ! implement the MPI-2/MPI-3 one-sided / shared-memory interfaces, so for
+  ! mpi-serial builds (CPP macro NO_MPI2, set by CIME for MPILIB=mpi-serial) a
+  ! single-task fallback is compiled instead: each "node-shared" array is a plain
+  ! local allocation (one task is its own node and its own leader, so there is no
+  ! cross-rank sharing and the leader sum-reduce is a no-op).  The F90 'mpi' module
+  ! (not mpif.h) is used because the TYPE(C_PTR) overloads of MPI_WIN_ALLOCATE_SHARED
+  ! / MPI_WIN_SHARED_QUERY are only guaranteed there (MPI-3.0).
+  !-----------------------------------------------------------------------------
+
+  use mpi
+  use, intrinsic :: iso_c_binding, only : c_ptr, c_f_pointer
+  use spmdMod   , only : mpicom
+  use abortutils, only : endrun
+
+  implicit none
+  private
+
+  public :: clm_shmem_alloc_i4_1d          ! allocate a node-shared default-integer rank-1 array
+  public :: clm_shmem_leader_allreduce_sum_i4 ! sum a node-shared array across nodes, in place
+  public :: clm_shmem_free                 ! free a node-shared array (MPI_Win_free)
+  public :: clm_shmem_fence                ! synchronize a window (publish writes)
+  public :: clm_shmem_is_leader            ! .true. on the leader (rank 0) of this node
+  public :: clm_shmem_leader_comm          ! communicator containing only node leaders
+  public :: clm_shmem_npes_per_node        ! number of ranks sharing this node
+
+  interface clm_shmem_free
+     module procedure clm_shmem_free_i4_1d
+  end interface clm_shmem_free
+
+  ! Sentinel window handle used by the mpi-serial fallback (no real MPI window).
+  integer, parameter :: SHMEM_WIN_NONE = -1
+
+  logical, save :: initialized = .false.
+  integer, save :: node_comm   = MPI_COMM_NULL  ! ranks sharing a node
+  integer, save :: leader_comm = MPI_COMM_NULL  ! one rank per node (the leaders)
+  integer, save :: node_rank   = 0
+  integer, save :: node_size   = 1
+  logical, save :: is_leader   = .true.
+
+contains
+
+  !=============================================================================
+  subroutine init_comms()
+    ! Lazily build the node-local and node-leader communicators.  Collective over
+    ! mpicom; safe to call from every shared-memory request.
+#ifndef NO_MPI2
+    integer :: ierr, color
+#endif
+
+    if (initialized) return
+
+#ifndef NO_MPI2
+    call mpi_comm_split_type(mpicom, MPI_COMM_TYPE_SHARED, 0, MPI_INFO_NULL, &
+                             node_comm, ierr)
+    call mpi_comm_rank(node_comm, node_rank, ierr)
+    call mpi_comm_size(node_comm, node_size, ierr)
+    is_leader = (node_rank == 0)
+
+    ! Communicator of node leaders only.  masterproc (global rank 0) is a leader.
+    if (is_leader) then
+       color = 0
+    else
+       color = MPI_UNDEFINED
+    end if
+    call mpi_comm_split(mpicom, color, 0, leader_comm, ierr)
+#else
+    ! mpi-serial: a single task is its own node and its own leader.
+    node_rank = 0
+    node_size = 1
+    is_leader = .true.
+#endif
+
+    initialized = .true.
+  end subroutine init_comms
+
+  !=============================================================================
+  subroutine clm_shmem_alloc_i4_1d(ptr, win, n)
+    ! Allocate a node-shared default-integer array of length n.  Only the node
+    ! leader requests storage; peers map the leader's contiguous segment.
+    integer, pointer, intent(out) :: ptr(:)
+    integer,          intent(out) :: win
+    integer,          intent(in)  :: n
+
+#ifndef NO_MPI2
+    integer(kind=MPI_ADDRESS_KIND) :: winsize, qsize
+    integer :: ierr, disp_unit, qdisp
+    integer :: itmp
+    type(c_ptr) :: baseptr
+#else
+    integer :: istat
+#endif
+
+    call init_comms()
+
+#ifndef NO_MPI2
+    disp_unit = storage_size(itmp) / 8   ! bytes per default integer (robust to -i8)
+    if (is_leader) then
+       winsize = int(n, MPI_ADDRESS_KIND) * int(disp_unit, MPI_ADDRESS_KIND)
+    else
+       winsize = 0_MPI_ADDRESS_KIND
+    end if
+
+    call mpi_win_allocate_shared(winsize, disp_unit, MPI_INFO_NULL, node_comm, &
+                                 baseptr, win, ierr)
+    if (ierr /= MPI_SUCCESS) call endrun('clm_shmem_mod: MPI_Win_allocate_shared failed')
+
+    ! Non-leaders learn the address of the leader's (rank 0) contiguous segment.
+    if (.not. is_leader) then
+       call mpi_win_shared_query(win, 0, qsize, qdisp, baseptr, ierr)
+       if (ierr /= MPI_SUCCESS) call endrun('clm_shmem_mod: MPI_Win_shared_query failed')
+    end if
+
+    call c_f_pointer(baseptr, ptr, [n])
+#else
+    ! mpi-serial: single task, no shared memory -- a plain local allocation.
+    allocate(ptr(n), stat=istat)
+    if (istat /= 0) call endrun('clm_shmem_mod: allocate failed (mpi-serial path)')
+    win = SHMEM_WIN_NONE
+#endif
+  end subroutine clm_shmem_alloc_i4_1d
+
+  !=============================================================================
+  subroutine clm_shmem_leader_allreduce_sum_i4(ptr, win, n)
+    ! Build a globally-summed array in the node-shared buffer ptr(1:n): fence so
+    ! every rank's stores are visible, then the node leaders sum their per-node
+    ! partials across nodes (over leader_comm) into the shared buffer, then fence
+    ! to publish the result to all ranks on the node.  Collective over node_comm;
+    ! every rank on the node must call it.
+    integer, pointer,    intent(inout) :: ptr(:)
+    integer,             intent(in)    :: win
+    integer,             intent(in)    :: n
+
+#ifndef NO_MPI2
+    integer, allocatable :: tmp(:)
+    integer :: ierr
+#endif
+
+    call clm_shmem_fence(win)             ! all node stores complete and visible to leader
+#ifndef NO_MPI2
+    if (is_leader) then
+       allocate(tmp(n))
+       call mpi_allreduce(ptr, tmp, n, MPI_INTEGER, MPI_SUM, leader_comm, ierr)
+       if (ierr /= MPI_SUCCESS) call endrun('clm_shmem_mod: MPI_Allreduce failed')
+       ptr(1:n) = tmp(1:n)
+       deallocate(tmp)
+    end if
+#else
+    ! mpi-serial: the single task owns the whole domain, so ptr already holds the
+    ! global array -- there is nothing to sum across nodes.
+#endif
+    call clm_shmem_fence(win)             ! publish global result to all node ranks
+  end subroutine clm_shmem_leader_allreduce_sum_i4
+
+  !=============================================================================
+  subroutine clm_shmem_fence(win)
+    ! Collective over the node communicator; synchronizes the window so stores
+    ! become visible to all ranks on the node.  A no-op for the mpi-serial path.
+    integer, intent(in) :: win
+#ifndef NO_MPI2
+    integer :: ierr
+    call mpi_win_fence(0, win, ierr)
+    if (ierr /= MPI_SUCCESS) call endrun('clm_shmem_mod: MPI_Win_fence failed')
+#endif
+  end subroutine clm_shmem_fence
+
+  !=============================================================================
+  subroutine clm_shmem_free_i4_1d(ptr, win)
+    ! Free the node-shared window and disassociate the pointer.  Collective over
+    ! the node communicator; a no-op when win == MPI_WIN_NULL.
+    integer, pointer       :: ptr(:)
+    integer, intent(inout) :: win
+#ifndef NO_MPI2
+    integer :: ierr
+    if (win /= MPI_WIN_NULL) then
+       call mpi_win_free(win, ierr)
+       if (ierr /= MPI_SUCCESS) call endrun('clm_shmem_mod: MPI_Win_free failed')
+    end if
+    if (associated(ptr)) nullify(ptr)
+    win = MPI_WIN_NULL
+#else
+    ! mpi-serial: ptr was a plain local allocation, so deallocate it.
+    if (associated(ptr)) deallocate(ptr)
+    win = SHMEM_WIN_NONE
+#endif
+  end subroutine clm_shmem_free_i4_1d
+
+  !=============================================================================
+  logical function clm_shmem_is_leader()
+    call init_comms()
+    clm_shmem_is_leader = is_leader
+  end function clm_shmem_is_leader
+
+  !=============================================================================
+  integer function clm_shmem_leader_comm()
+    call init_comms()
+    clm_shmem_leader_comm = leader_comm
+  end function clm_shmem_leader_comm
+
+  !=============================================================================
+  integer function clm_shmem_npes_per_node()
+    call init_comms()
+    clm_shmem_npes_per_node = node_size
+  end function clm_shmem_npes_per_node
+
+end module clm_shmem_mod