MpiDirectSendrecvVariableSynchronizeDispatcher.cc

// -*- tab-width: 2; indent-tabs-mode: nil; coding: utf-8-with-signature -*-
//-----------------------------------------------------------------------------
// Copyright 2000-2026 CEA (www.cea.fr) IFPEN (www.ifpenergiesnouvelles.com)
// See the top-level COPYRIGHT file for details.
// SPDX-License-Identifier: Apache-2.0
//-----------------------------------------------------------------------------
/*---------------------------------------------------------------------------*/
/* MpiDirectSendrecvVariableSynchronizeDispatcher.cc           (C) 2000-2025 */
/*                                                                           */
/* Specific MPI management of variable synchronizations.                     */
/*---------------------------------------------------------------------------*/
/*---------------------------------------------------------------------------*/
 
#include "arcane/utils/MemoryView.h"
 
#include "arcane/parallel/mpi/MpiParallelMng.h"
#include "arcane/parallel/mpi/MpiDatatypeList.h"
#include "arcane/parallel/mpi/MpiDatatype.h"
#include "arcane/parallel/mpi/MpiTimeInterval.h"
#include "arcane/parallel/IStat.h"
 
#include "arcane/impl/IDataSynchronizeBuffer.h"
#include "arcane/impl/IDataSynchronizeImplementation.h"
 
#include "arccore/message_passing_mpi/internal/MpiAdapter.h"
 
/*---------------------------------------------------------------------------*/
/*---------------------------------------------------------------------------*/
 
namespace Arcane
{
 
/*---------------------------------------------------------------------------*/
/*---------------------------------------------------------------------------*/

class MpiDirectSendrecvVariableSynchronizerDispatcher
: public AbstractDataSynchronizeImplementation
{
 public:
 
  class Factory;
  explicit MpiDirectSendrecvVariableSynchronizerDispatcher(Factory* f);
 
 protected:
 
  void compute() override {}
  void beginSynchronize(IDataSynchronizeBuffer* vs_buf) override;
  void endSynchronize(IDataSynchronizeBuffer*) override
  {
    // With this implementation, we do not need this function.
  }
 
 private:
 
  MpiParallelMng* m_mpi_parallel_mng;
};
 
/*---------------------------------------------------------------------------*/
/*---------------------------------------------------------------------------*/
 
class MpiDirectSendrecvVariableSynchronizerDispatcher::Factory
: public IDataSynchronizeImplementationFactory
{
 public:
 
  Factory(MpiParallelMng* mpi_pm)
  : m_mpi_parallel_mng(mpi_pm)
  {}
 
  Ref<IDataSynchronizeImplementation> createInstance() override
  {
    auto* x = new MpiDirectSendrecvVariableSynchronizerDispatcher(this);
    return makeRef<IDataSynchronizeImplementation>(x);
  }
 
 public:
 
  MpiParallelMng* m_mpi_parallel_mng = nullptr;
};
 
/*---------------------------------------------------------------------------*/
/*---------------------------------------------------------------------------*/
 
extern "C++" Ref<IDataSynchronizeImplementationFactory>
arcaneCreateMpiDirectSendrecvVariableSynchronizerFactory(MpiParallelMng* mpi_pm)
{
  auto* x = new MpiDirectSendrecvVariableSynchronizerDispatcher::Factory(mpi_pm);
  return makeRef<IDataSynchronizeImplementationFactory>(x);
}
 
/*---------------------------------------------------------------------------*/
/*---------------------------------------------------------------------------*/
 
MpiDirectSendrecvVariableSynchronizerDispatcher::
MpiDirectSendrecvVariableSynchronizerDispatcher(Factory* f)
: m_mpi_parallel_mng(f->m_mpi_parallel_mng)
{
}
 
/*---------------------------------------------------------------------------*/
/*---------------------------------------------------------------------------*/
 
void MpiDirectSendrecvVariableSynchronizerDispatcher::
beginSynchronize(IDataSynchronizeBuffer* vs_buf)
{
  Int32 nb_message = vs_buf->nbRank();
 
  constexpr int serialize_tag = 523;
 
  MpiParallelMng* pm = m_mpi_parallel_mng;
  MpiDatatypeList* dtlist = pm->datatypes();
  const MPI_Datatype mpi_dt = dtlist->datatype(Byte())->datatype();
 
  double sync_copy_send_time = 0.0;
  double sync_copy_recv_time = 0.0;
  double sync_wait_time = 0.0;
 
  {
    MpiTimeInterval tit(&sync_copy_send_time);
    vs_buf->copyAllSend();
  }
 
  {
    MpiTimeInterval tit(&sync_wait_time);
    for (Integer i = 0; i < nb_message; ++i) {
      Int32 target_rank = vs_buf->targetRank(i);
      auto rbuf = vs_buf->receiveBuffer(i).bytes().smallView();
      auto sbuf = vs_buf->sendBuffer(i).bytes().smallView();
 
      MPI_Sendrecv(sbuf.data(), sbuf.size(), mpi_dt, target_rank, serialize_tag,
                   rbuf.data(), rbuf.size(), mpi_dt, target_rank, serialize_tag,
                   pm->communicator(), MPI_STATUS_IGNORE);
    }
  }
 
  {
    MpiTimeInterval tit(&sync_copy_recv_time);
    vs_buf->copyAllReceive();
  }
 
  pm->stat()->add("SyncCopySend", sync_copy_send_time, 1);
  pm->stat()->add("SyncWait", sync_wait_time, 1);
  pm->stat()->add("SyncCopyRecv", sync_copy_recv_time, 1);
}
 
/*---------------------------------------------------------------------------*/
/*---------------------------------------------------------------------------*/
 
} // End namespace Arcane
 
/*---------------------------------------------------------------------------*/
/*---------------------------------------------------------------------------*/