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37 * \brief Implements PME-PP communication using CUDA
40 * \author Alan Gray <alang@nvidia.com>
42 * \ingroup module_ewald
46 #include "pme_force_sender_gpu_impl.h"
50 #include "gromacs/gpu_utils/cudautils.cuh"
51 #include "gromacs/gpu_utils/gpueventsynchronizer.cuh"
52 #include "gromacs/utility/gmxmpi.h"
57 /*! \brief Create PME-PP GPU communication object */
58 PmeForceSenderGpu::Impl::Impl(GpuEventSynchronizer* pmeForcesReady,
60 gmx::ArrayRef<PpRanks> ppRanks) :
61 pmeForcesReady_(pmeForcesReady), comm_(comm), ppRanks_(ppRanks)
65 PmeForceSenderGpu::Impl::~Impl() = default;
67 /*! \brief sends force buffer address to PP ranks */
68 void PmeForceSenderGpu::Impl::sendForceBufferAddressToPpRanks(DeviceBuffer<Float3> d_f)
70 // Need to send address to PP rank only for thread-MPI as PP rank pulls
71 // data using cudamemcpy
79 for (const auto& receiver : ppRanks_)
82 ind_end = ind_start + receiver.numAtoms;
84 // Data will be transferred directly from GPU.
85 Float3* sendBuf = &d_f[ind_start];
87 MPI_Send(&sendBuf, sizeof(Float3*), MPI_BYTE, receiver.rankId, 0, comm_);
90 GMX_UNUSED_VALUE(d_f);
94 /*! \brief Send PME synchronizer directly using CUDA memory copy */
95 void PmeForceSenderGpu::Impl::sendFSynchronizerToPpCudaDirect(int ppRank)
97 GMX_ASSERT(GMX_THREAD_MPI,
98 "sendFSynchronizerToPpCudaDirect is expected to be called only for Thread-MPI");
100 // Data will be pulled directly from PP task
102 // TODO Using MPI_Isend would be more efficient, particularly when
103 // sending to multiple PP ranks
104 MPI_Send(&pmeForcesReady_, sizeof(GpuEventSynchronizer*), MPI_BYTE, ppRank, 0, comm_);
106 GMX_UNUSED_VALUE(ppRank);
110 /*! \brief Send PME data directly using CUDA-aware MPI */
111 void PmeForceSenderGpu::Impl::sendFToPpCudaMpi(DeviceBuffer<RVec> sendbuf,
115 MPI_Request* request)
117 GMX_ASSERT(GMX_LIB_MPI, "sendFToPpCudaMpi is expected to be called only for Lib-MPI");
120 // if using GPU direct comm with CUDA-aware MPI, make sure forces are ready on device
121 // before sending it to PP ranks
122 pmeForcesReady_->waitForEvent();
124 MPI_Isend(sendbuf[offset], numBytes, MPI_BYTE, ppRank, 0, comm_, request);
127 GMX_UNUSED_VALUE(sendbuf);
128 GMX_UNUSED_VALUE(offset);
129 GMX_UNUSED_VALUE(numBytes);
130 GMX_UNUSED_VALUE(ppRank);
131 GMX_UNUSED_VALUE(request);
135 PmeForceSenderGpu::PmeForceSenderGpu(GpuEventSynchronizer* pmeForcesReady,
137 gmx::ArrayRef<PpRanks> ppRanks) :
138 impl_(new Impl(pmeForcesReady, comm, ppRanks))
142 PmeForceSenderGpu::~PmeForceSenderGpu() = default;
144 void PmeForceSenderGpu::sendForceBufferAddressToPpRanks(DeviceBuffer<RVec> d_f)
146 impl_->sendForceBufferAddressToPpRanks(d_f);
149 void PmeForceSenderGpu::sendFSynchronizerToPpCudaDirect(int ppRank)
151 impl_->sendFSynchronizerToPpCudaDirect(ppRank);
154 void PmeForceSenderGpu::sendFToPpCudaMpi(DeviceBuffer<RVec> sendbuf,
158 MPI_Request* request)
160 impl_->sendFToPpCudaMpi(sendbuf, offset, numBytes, ppRank, request);