/* -*- Mode: C; c-basic-offset:4 ; indent-tabs-mode:nil ; -*- */
/*
 *  (C) 2010 by Argonne National Laboratory.
 *      See COPYRIGHT in top-level directory.
 */

#include "mpiimpl.h"

/*
=== BEGIN_MPI_T_CVAR_INFO_BLOCK ===

cvars:
    - name        : MPIR_CVAR_IALLREDUCE_INTRA_ALGORITHM
      category    : COLLECTIVE
      type        : string
      default     : auto
      class       : device
      verbosity   : MPI_T_VERBOSITY_USER_BASIC
      scope       : MPI_T_SCOPE_ALL_EQ
      description : |-
        Variable to select iallreduce algorithm
        auto                     - Internal algorithm selection
        naive                    - Force naive algorithm
        recursive_doubling       - Force recursive doubling algorithm
        reduce_scatter_allgather - Force reduce scatter allgather algorithm

    - name        : MPIR_CVAR_IALLREDUCE_INTER_ALGORITHM
      category    : COLLECTIVE
      type        : string
      default     : auto
      class       : device
      verbosity   : MPI_T_VERBOSITY_USER_BASIC
      scope       : MPI_T_SCOPE_ALL_EQ
      description : |-
        Variable to select iallreduce algorithm
        auto                      - Internal algorithm selection
        remote_reduce_local_bcast - Force remote-reduce-local-bcast algorithm

    - name        : MPIR_CVAR_IALLREDUCE_DEVICE_COLLECTIVE
      category    : COLLECTIVE
      type        : boolean
      default     : true
      class       : device
      verbosity   : MPI_T_VERBOSITY_USER_BASIC
      scope       : MPI_T_SCOPE_ALL_EQ
      description : >-
        If set to true, MPI_Iallreduce will allow the device to override the
        MPIR-level collective algorithms. The device still has the
        option to call the MPIR-level algorithms manually.
        If set to false, the device-level iallreduce function will not be
        called.

=== END_MPI_T_CVAR_INFO_BLOCK ===
*/

/* -- Begin Profiling Symbol Block for routine MPI_Iallreduce */
#if defined(HAVE_PRAGMA_WEAK)
#pragma weak MPI_Iallreduce = PMPI_Iallreduce
#elif defined(HAVE_PRAGMA_HP_SEC_DEF)
#pragma _HP_SECONDARY_DEF PMPI_Iallreduce  MPI_Iallreduce
#elif defined(HAVE_PRAGMA_CRI_DUP)
#pragma _CRI duplicate MPI_Iallreduce as PMPI_Iallreduce
#elif defined(HAVE_WEAK_ATTRIBUTE)
int MPI_Iallreduce(const void *sendbuf, void *recvbuf, int count, MPI_Datatype datatype,
                   MPI_Op op, MPI_Comm comm, MPI_Request * request)
    __attribute__ ((weak, alias("PMPI_Iallreduce")));
#endif
/* -- End Profiling Symbol Block */

/* Define MPICH_MPI_FROM_PMPI if weak symbols are not supported to build
   the MPI routines */
#ifndef MPICH_MPI_FROM_PMPI
#undef MPI_Iallreduce
#define MPI_Iallreduce PMPI_Iallreduce

#undef FUNCNAME
#define FUNCNAME MPIR_Iallreduce_sched_intra_auto
#undef FCNAME
#define FCNAME MPL_QUOTE(FUNCNAME)
int MPIR_Iallreduce_sched_intra_auto(const void *sendbuf, void *recvbuf, int count,
                                     MPI_Datatype datatype, MPI_Op op, MPIR_Comm * comm_ptr,
                                     MPIR_Sched_t s)
{
    int mpi_errno = MPI_SUCCESS;
    int is_homogeneous, pof2, type_size;

    MPIR_Assert(comm_ptr->comm_kind == MPIR_COMM_KIND__INTRACOMM);

    is_homogeneous = TRUE;
#ifdef MPID_HAS_HETERO
    if (comm_ptr->is_hetero)
        is_homogeneous = FALSE;
#endif

    if (!is_homogeneous) {
        mpi_errno =
            MPIR_Iallreduce_sched_intra_naive(sendbuf, recvbuf, count, datatype, op, comm_ptr, s);
        if (mpi_errno)
            MPIR_ERR_POP(mpi_errno);
        goto fn_exit;
    }

    MPIR_Datatype_get_size_macro(datatype, type_size);

    /* get nearest power-of-two less than or equal to number of ranks in the communicator */
    pof2 = comm_ptr->pof2;

    /* If op is user-defined or count is less than pof2, use
     * recursive doubling algorithm. Otherwise do a reduce-scatter
     * followed by allgather. (If op is user-defined,
     * derived datatypes are allowed and the user could pass basic
     * datatypes on one process and derived on another as long as
     * the type maps are the same. Breaking up derived
     * datatypes to do the reduce-scatter is tricky, therefore
     * using recursive doubling in that case.) */

    if ((count * type_size <= MPIR_CVAR_ALLREDUCE_SHORT_MSG_SIZE) ||
        (HANDLE_GET_KIND(op) != HANDLE_KIND_BUILTIN) || (count < pof2)) {
        /* use recursive doubling */
        mpi_errno =
            MPIR_Iallreduce_sched_intra_recursive_doubling(sendbuf, recvbuf, count, datatype, op,
                                                           comm_ptr, s);
        if (mpi_errno)
            MPIR_ERR_POP(mpi_errno);
    } else {
        /* do a reduce-scatter followed by allgather */
        mpi_errno =
            MPIR_Iallreduce_sched_intra_reduce_scatter_allgather(sendbuf, recvbuf, count, datatype,
                                                                 op, comm_ptr, s);
        if (mpi_errno)
            MPIR_ERR_POP(mpi_errno);
    }

  fn_exit:
    return mpi_errno;
  fn_fail:
    goto fn_exit;
}

#undef FUNCNAME
#define FUNCNAME MPIR_Iallreduce_sched_inter_auto
#undef FCNAME
#define FCNAME MPL_QUOTE(FUNCNAME)
int MPIR_Iallreduce_sched_inter_auto(const void *sendbuf, void *recvbuf, int count,
                                     MPI_Datatype datatype, MPI_Op op, MPIR_Comm * comm_ptr,
                                     MPIR_Sched_t s)
{
    int mpi_errno = MPI_SUCCESS;

    mpi_errno = MPIR_Iallreduce_sched_inter_remote_reduce_local_bcast(sendbuf, recvbuf, count,
                                                                      datatype, op, comm_ptr, s);

    return mpi_errno;
}


#undef FUNCNAME
#define FUNCNAME MPIR_Iallreduce_sched_impl
#undef FCNAME
#define FCNAME MPL_QUOTE(FUNCNAME)
int MPIR_Iallreduce_sched_impl(const void *sendbuf, void *recvbuf, int count, MPI_Datatype datatype,
                               MPI_Op op, MPIR_Comm * comm_ptr, MPIR_Sched_t s)
{
    int mpi_errno = MPI_SUCCESS;

    if (comm_ptr->comm_kind == MPIR_COMM_KIND__INTRACOMM) {
        if (comm_ptr->hierarchy_kind == MPIR_COMM_HIERARCHY_KIND__PARENT &&
            MPIR_CVAR_ENABLE_SMP_COLLECTIVES && MPIR_CVAR_ENABLE_SMP_ALLREDUCE) {
            mpi_errno =
                MPIR_Iallreduce_sched_intra_smp(sendbuf, recvbuf, count, datatype, op, comm_ptr, s);
        } else {
            /* intracommunicator */
            switch (MPIR_Iallreduce_intra_algo_choice) {
                case MPIR_IALLREDUCE_INTRA_ALGO_NAIVE:
                    mpi_errno = MPIR_Iallreduce_sched_intra_naive(sendbuf, recvbuf, count,
                                                                  datatype, op, comm_ptr, s);
                    break;
                case MPIR_IALLREDUCE_INTRA_ALGO_RECURSIVE_DOUBLING:
                    mpi_errno =
                        MPIR_Iallreduce_sched_intra_recursive_doubling(sendbuf, recvbuf, count,
                                                                       datatype, op, comm_ptr, s);
                    break;
                case MPIR_IALLREDUCE_INTRA_ALGO_REDUCE_SCATTER_ALLGATHER:
                    mpi_errno =
                        MPIR_Iallreduce_sched_intra_reduce_scatter_allgather(sendbuf, recvbuf,
                                                                             count, datatype, op,
                                                                             comm_ptr, s);
                    break;
                case MPIR_IALLREDUCE_INTRA_ALGO_AUTO:
                    MPL_FALLTHROUGH;
                default:
                    mpi_errno = MPIR_Iallreduce_sched_intra_auto(sendbuf, recvbuf, count,
                                                                 datatype, op, comm_ptr, s);
                    break;
            }
        }
    } else {
        /* intercommunicator */
        switch (MPIR_Iallreduce_inter_algo_choice) {
            case MPIR_IALLREDUCE_INTER_ALGO_REMOTE_REDUCE_LOCAL_BCAST:
                mpi_errno =
                    MPIR_Iallreduce_sched_inter_remote_reduce_local_bcast(sendbuf, recvbuf, count,
                                                                          datatype, op, comm_ptr,
                                                                          s);
                break;
            case MPIR_IALLREDUCE_INTER_ALGO_AUTO:
                MPL_FALLTHROUGH;
            default:
                mpi_errno = MPIR_Iallreduce_sched_inter_auto(sendbuf, recvbuf, count,
                                                             datatype, op, comm_ptr, s);
                break;
        }

    }
    return mpi_errno;
}

#undef FUNCNAME
#define FUNCNAME MPIR_Iallreduce_sched
#undef FCNAME
#define FCNAME MPL_QUOTE(FUNCNAME)
int MPIR_Iallreduce_sched(const void *sendbuf, void *recvbuf, int count, MPI_Datatype datatype,
                          MPI_Op op, MPIR_Comm * comm_ptr, MPIR_Sched_t s)
{
    int mpi_errno = MPI_SUCCESS;

    if (MPIR_CVAR_IALLREDUCE_DEVICE_COLLECTIVE && MPIR_CVAR_DEVICE_COLLECTIVES) {
        mpi_errno = MPID_Iallreduce_sched(sendbuf, recvbuf, count, datatype, op, comm_ptr, s);
    } else {
        mpi_errno = MPIR_Iallreduce_sched_impl(sendbuf, recvbuf, count, datatype, op, comm_ptr, s);
    }

    return mpi_errno;
}

#undef FUNCNAME
#define FUNCNAME MPIR_Iallreduce_impl
#undef FCNAME
#define FCNAME MPL_QUOTE(FUNCNAME)
int MPIR_Iallreduce_impl(const void *sendbuf, void *recvbuf, int count,
                         MPI_Datatype datatype, MPI_Op op, MPIR_Comm * comm_ptr,
                         MPIR_Request ** request)
{
    int mpi_errno = MPI_SUCCESS;
    int tag = -1;
    MPIR_Sched_t s = MPIR_SCHED_NULL;

    *request = NULL;

    mpi_errno = MPIR_Sched_next_tag(comm_ptr, &tag);
    if (mpi_errno)
        MPIR_ERR_POP(mpi_errno);
    mpi_errno = MPIR_Sched_create(&s);
    if (mpi_errno)
        MPIR_ERR_POP(mpi_errno);

    mpi_errno = MPIR_Iallreduce_sched(sendbuf, recvbuf, count, datatype, op, comm_ptr, s);
    if (mpi_errno)
        MPIR_ERR_POP(mpi_errno);

    mpi_errno = MPIR_Sched_start(&s, comm_ptr, tag, request);
    if (mpi_errno)
        MPIR_ERR_POP(mpi_errno);

  fn_exit:
    return mpi_errno;
  fn_fail:
    goto fn_exit;
}

#undef FUNCNAME
#define FUNCNAME MPIR_Iallreduce
#undef FCNAME
#define FCNAME MPL_QUOTE(FUNCNAME)
int MPIR_Iallreduce(const void *sendbuf, void *recvbuf, int count,
                    MPI_Datatype datatype, MPI_Op op, MPIR_Comm * comm_ptr, MPIR_Request ** request)
{
    int mpi_errno = MPI_SUCCESS;

    if (MPIR_CVAR_IALLREDUCE_DEVICE_COLLECTIVE && MPIR_CVAR_DEVICE_COLLECTIVES) {
        mpi_errno = MPID_Iallreduce(sendbuf, recvbuf, count, datatype, op, comm_ptr, request);
    } else {
        mpi_errno = MPIR_Iallreduce_impl(sendbuf, recvbuf, count, datatype, op, comm_ptr, request);
    }

    return mpi_errno;
}

#endif /* MPICH_MPI_FROM_PMPI */

#undef FUNCNAME
#define FUNCNAME MPI_Iallreduce
#undef FCNAME
#define FCNAME MPL_QUOTE(FUNCNAME)
/*@
MPI_Iallreduce - Combines values from all processes and distributes the result
                 back to all processes in a nonblocking way

Input Parameters:
+ sendbuf - starting address of the send buffer (choice)
. count - number of elements in send buffer (non-negative integer)
. datatype - data type of elements of send buffer (handle)
. op - operation (handle)
- comm - communicator (handle)

Output Parameters:
+ recvbuf - starting address of the receive buffer (choice)
- request - communication request (handle)

.N ThreadSafe

.N Fortran

.N Errors
@*/
int MPI_Iallreduce(const void *sendbuf, void *recvbuf, int count,
                   MPI_Datatype datatype, MPI_Op op, MPI_Comm comm, MPI_Request * request)
{
    int mpi_errno = MPI_SUCCESS;
    MPIR_Comm *comm_ptr = NULL;
    MPIR_Request *request_ptr = NULL;
    MPIR_FUNC_TERSE_STATE_DECL(MPID_STATE_MPI_IALLREDUCE);

    MPID_THREAD_CS_ENTER(GLOBAL, MPIR_THREAD_GLOBAL_ALLFUNC_MUTEX);
    MPIR_FUNC_TERSE_ENTER(MPID_STATE_MPI_IALLREDUCE);

    /* Validate parameters, especially handles needing to be converted */
#ifdef HAVE_ERROR_CHECKING
    {
        MPID_BEGIN_ERROR_CHECKS;
        {
            MPIR_ERRTEST_DATATYPE(datatype, "datatype", mpi_errno);
            MPIR_ERRTEST_COUNT(count, mpi_errno);
            MPIR_ERRTEST_OP(op, mpi_errno);
            MPIR_ERRTEST_COMM(comm, mpi_errno);

            /* TODO more checks may be appropriate */
        }
        MPID_END_ERROR_CHECKS;
    }
#endif /* HAVE_ERROR_CHECKING */

    /* Convert MPI object handles to object pointers */
    MPIR_Comm_get_ptr(comm, comm_ptr);

    /* Validate parameters and objects (post conversion) */
#ifdef HAVE_ERROR_CHECKING
    {
        MPID_BEGIN_ERROR_CHECKS;
        {
            MPIR_Comm_valid_ptr(comm_ptr, mpi_errno, FALSE);
            if (HANDLE_GET_KIND(datatype) != HANDLE_KIND_BUILTIN) {
                MPIR_Datatype *datatype_ptr = NULL;
                MPIR_Datatype_get_ptr(datatype, datatype_ptr);
                MPIR_Datatype_valid_ptr(datatype_ptr, mpi_errno);
                if (mpi_errno != MPI_SUCCESS)
                    goto fn_fail;
                MPIR_Datatype_committed_ptr(datatype_ptr, mpi_errno);
                if (mpi_errno != MPI_SUCCESS)
                    goto fn_fail;
            }

            if (HANDLE_GET_KIND(op) != HANDLE_KIND_BUILTIN) {
                MPIR_Op *op_ptr = NULL;
                MPIR_Op_get_ptr(op, op_ptr);
                MPIR_Op_valid_ptr(op_ptr, mpi_errno);
            } else if (HANDLE_GET_KIND(op) == HANDLE_KIND_BUILTIN) {
                mpi_errno = (*MPIR_OP_HDL_TO_DTYPE_FN(op)) (datatype);
            }
            if (mpi_errno != MPI_SUCCESS)
                goto fn_fail;

            if (comm_ptr->comm_kind == MPIR_COMM_KIND__INTERCOMM)
                MPIR_ERRTEST_SENDBUF_INPLACE(sendbuf, count, mpi_errno);

            if (sendbuf != MPI_IN_PLACE)
                MPIR_ERRTEST_USERBUFFER(sendbuf, count, datatype, mpi_errno);

            MPIR_ERRTEST_ARGNULL(request, "request", mpi_errno);

            if (comm_ptr->comm_kind == MPIR_COMM_KIND__INTRACOMM && count != 0 &&
                sendbuf != MPI_IN_PLACE)
                MPIR_ERRTEST_ALIAS_COLL(sendbuf, recvbuf, mpi_errno);

            /* TODO more checks may be appropriate (counts, in_place, buffer aliasing, etc) */
        }
        MPID_END_ERROR_CHECKS;
    }
#endif /* HAVE_ERROR_CHECKING */

    /* ... body of routine ...  */

    mpi_errno = MPIR_Iallreduce(sendbuf, recvbuf, count, datatype, op, comm_ptr, &request_ptr);
    if (mpi_errno)
        MPIR_ERR_POP(mpi_errno);

    /* return the handle of the request to the user */
    if (request_ptr)
        *request = request_ptr->handle;
    else
        *request = MPI_REQUEST_NULL;

    /* ... end of body of routine ... */

  fn_exit:
    MPIR_FUNC_TERSE_EXIT(MPID_STATE_MPI_IALLREDUCE);
    MPID_THREAD_CS_EXIT(GLOBAL, MPIR_THREAD_GLOBAL_ALLFUNC_MUTEX);
    return mpi_errno;

  fn_fail:
    /* --BEGIN ERROR HANDLING-- */
#ifdef HAVE_ERROR_CHECKING
    {
        mpi_errno =
            MPIR_Err_create_code(mpi_errno, MPIR_ERR_RECOVERABLE, FCNAME, __LINE__, MPI_ERR_OTHER,
                                 "**mpi_iallreduce", "**mpi_iallreduce %p %p %d %D %O %C %p",
                                 sendbuf, recvbuf, count, datatype, op, comm, request);
    }
#endif
    mpi_errno = MPIR_Err_return_comm(comm_ptr, FCNAME, mpi_errno);
    goto fn_exit;
    /* --END ERROR HANDLING-- */
}
