src/gromacs/ewald/pme_coordinate_receiver_gpu_impl.cu

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  35 /*! \internal \file
  36  *
  37  * \brief Implements class which recieves coordinates to GPU memory on PME task using CUDA
  38  *
  39  *
  40  * \author Alan Gray <alang@nvidia.com>
  41  *
  42  * \ingroup module_ewald
  43  */
  44 #include "gmxpre.h"
  45
  46 #include "gromacs/ewald/pme_pp_communication.h"
  47 #include "pme_coordinate_receiver_gpu_impl.h"
  48
  49 #include "config.h"
  50
  51 #include "gromacs/ewald/pme_force_sender_gpu.h"
  52 #include "gromacs/gpu_utils/cudautils.cuh"
  53 #include "gromacs/gpu_utils/gpueventsynchronizer.h"
  54 #include "gromacs/utility/gmxmpi.h"
  55
  56 namespace gmx
  57 {
  58
  59 PmeCoordinateReceiverGpu::Impl::Impl(const DeviceStream&    pmeStream,
  60                                      MPI_Comm               comm,
  61                                      gmx::ArrayRef<PpRanks> ppRanks) :
  62     pmeStream_(pmeStream), comm_(comm), ppRanks_(ppRanks)
  63 {
  64     request_.resize(ppRanks.size());
  65     ppSync_.resize(ppRanks.size());
  66 }
  67
  68 PmeCoordinateReceiverGpu::Impl::~Impl() = default;
  69
  70 void PmeCoordinateReceiverGpu::Impl::sendCoordinateBufferAddressToPpRanks(DeviceBuffer<RVec> d_x)
  71 {
  72     // Need to send address to PP rank only for thread-MPI as PP rank pushes data using cudamemcpy
  73     if (GMX_THREAD_MPI)
  74     {
  75         int ind_start = 0;
  76         int ind_end   = 0;
  77         for (const auto& receiver : ppRanks_)
  78         {
  79             ind_start = ind_end;
  80             ind_end   = ind_start + receiver.numAtoms;
  81
  82             // Data will be transferred directly from GPU.
  83             void* sendBuf = reinterpret_cast<void*>(&d_x[ind_start]);
  84 #if GMX_MPI
  85             MPI_Send(&sendBuf, sizeof(void**), MPI_BYTE, receiver.rankId, 0, comm_);
  86 #else
  87             GMX_UNUSED_VALUE(sendBuf);
  88 #endif
  89         }
  90     }
  91 }
  92
  93 /*! \brief Receive coordinate synchronizer pointer from the PP ranks. */
  94 void PmeCoordinateReceiverGpu::Impl::receiveCoordinatesSynchronizerFromPpCudaDirect(int ppRank)
  95 {
  96     GMX_ASSERT(GMX_THREAD_MPI,
  97                "receiveCoordinatesSynchronizerFromPpCudaDirect is expected to be called only for "
  98                "Thread-MPI");
  99
 100     // Data will be pushed directly from PP task
 101
 102 #if GMX_MPI
 103     // Receive event from PP task
 104     // NOLINTNEXTLINE(bugprone-sizeof-expression)
 105     MPI_Irecv(&ppSync_[recvCount_], sizeof(GpuEventSynchronizer*), MPI_BYTE, ppRank, 0, comm_, &request_[recvCount_]);
 106     recvCount_++;
 107 #else
 108     GMX_UNUSED_VALUE(ppRank);
 109 #endif
 110 }
 111
 112 /*! \brief Receive coordinate data using CUDA-aware MPI */
 113 void PmeCoordinateReceiverGpu::Impl::launchReceiveCoordinatesFromPpCudaMpi(DeviceBuffer<RVec> recvbuf,
 114                                                                            int numAtoms,
 115                                                                            int numBytes,
 116                                                                            int ppRank)
 117 {
 118     GMX_ASSERT(GMX_LIB_MPI,
 119                "launchReceiveCoordinatesFromPpCudaMpi is expected to be called only for Lib-MPI");
 120
 121 #if GMX_MPI
 122     MPI_Irecv(&recvbuf[numAtoms], numBytes, MPI_BYTE, ppRank, eCommType_COORD_GPU, comm_, &request_[recvCount_++]);
 123 #else
 124     GMX_UNUSED_VALUE(recvbuf);
 125     GMX_UNUSED_VALUE(numAtoms);
 126     GMX_UNUSED_VALUE(numBytes);
 127     GMX_UNUSED_VALUE(ppRank);
 128 #endif
 129 }
 130
 131 void PmeCoordinateReceiverGpu::Impl::synchronizeOnCoordinatesFromPpRanks()
 132 {
 133     if (recvCount_ > 0)
 134     {
 135         // ensure PME calculation doesn't commence until coordinate data/remote events
 136         // has been transferred
 137 #if GMX_MPI
 138         MPI_Waitall(recvCount_, request_.data(), MPI_STATUS_IGNORE);
 139 #endif
 140
 141         // Make PME stream wait on PP to PME data trasnfer events
 142         if (GMX_THREAD_MPI)
 143         {
 144             for (int i = 0; i < recvCount_; i++)
 145             {
 146                 ppSync_[i]->enqueueWaitEvent(pmeStream_);
 147             }
 148         }
 149
 150         // reset receive counter
 151         recvCount_ = 0;
 152     }
 153 }
 154
 155 PmeCoordinateReceiverGpu::PmeCoordinateReceiverGpu(const DeviceStream&    pmeStream,
 156                                                    MPI_Comm               comm,
 157                                                    gmx::ArrayRef<PpRanks> ppRanks) :
 158     impl_(new Impl(pmeStream, comm, ppRanks))
 159 {
 160 }
 161
 162 PmeCoordinateReceiverGpu::~PmeCoordinateReceiverGpu() = default;
 163
 164 void PmeCoordinateReceiverGpu::sendCoordinateBufferAddressToPpRanks(DeviceBuffer<RVec> d_x)
 165 {
 166     impl_->sendCoordinateBufferAddressToPpRanks(d_x);
 167 }
 168
 169 void PmeCoordinateReceiverGpu::receiveCoordinatesSynchronizerFromPpCudaDirect(int ppRank)
 170 {
 171     impl_->receiveCoordinatesSynchronizerFromPpCudaDirect(ppRank);
 172 }
 173
 174 void PmeCoordinateReceiverGpu::launchReceiveCoordinatesFromPpCudaMpi(DeviceBuffer<RVec> recvbuf,
 175                                                                      int                numAtoms,
 176                                                                      int                numBytes,
 177                                                                      int                ppRank)
 178 {
 179     impl_->launchReceiveCoordinatesFromPpCudaMpi(recvbuf, numAtoms, numBytes, ppRank);
 180 }
 181
 182 void PmeCoordinateReceiverGpu::synchronizeOnCoordinatesFromPpRanks()
 183 {
 184     impl_->synchronizeOnCoordinatesFromPpRanks();
 185 }
 186
 187 } // namespace gmx