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37 * \brief Declares CUDA implementation of GPU Halo Exchange.
39 * This header file is needed to include from both the device-side
40 * kernels file, and the host-side management code.
42 * \author Alan Gray <alang@nvidia.com>
44 * \ingroup module_domdec
46 #ifndef GMX_DOMDEC_GPUHALOEXCHANGE_IMPL_H
47 #define GMX_DOMDEC_GPUHALOEXCHANGE_IMPL_H
49 #include "gromacs/domdec/gpuhaloexchange.h"
50 #include "gromacs/gpu_utils/device_context.h"
51 #include "gromacs/gpu_utils/gpueventsynchronizer.cuh"
52 #include "gromacs/gpu_utils/hostallocator.h"
53 #include "gromacs/utility/gmxmpi.h"
58 /*! \brief switch for whether coordinates or force halo is being applied */
59 enum class HaloQuantity
65 /*! \internal \brief Class with interfaces and data for GPU Halo Exchange */
66 class GpuHaloExchange::Impl
70 /*! \brief Creates GPU Halo Exchange object.
72 * \param [inout] dd domdec structure
73 * \param [in] mpi_comm_mysim communicator used for simulation
74 * \param [in] deviceContext GPU device context
75 * \param [in] localStream local NB CUDA stream
76 * \param [in] nonLocalStream non-local NB CUDA stream
77 * \param [in] pulse the communication pulse for this instance
79 Impl(gmx_domdec_t* dd,
80 MPI_Comm mpi_comm_mysim,
81 const DeviceContext& deviceContext,
88 * (Re-) Initialization for GPU halo exchange
89 * \param [in] d_coordinatesBuffer pointer to coordinates buffer in GPU memory
90 * \param [in] d_forcesBuffer pointer to forces buffer in GPU memory
92 void reinitHalo(float3* d_coordinatesBuffer, float3* d_forcesBuffer);
96 * GPU halo exchange of coordinates buffer
97 * \param [in] box Coordinate box (from which shifts will be constructed)
98 * \param [in] coordinatesReadyOnDeviceEvent event recorded when coordinates have been copied to device
100 void communicateHaloCoordinates(const matrix box, GpuEventSynchronizer* coordinatesReadyOnDeviceEvent);
102 /*! \brief GPU halo exchange of force buffer
103 * \param[in] accumulateForces True if forces should accumulate, otherwise they are set
105 void communicateHaloForces(bool accumulateForces);
107 /*! \brief Get the event synchronizer for the forces ready on device.
108 * \returns The event to synchronize the stream that consumes forces on device.
110 GpuEventSynchronizer* getForcesReadyOnDeviceEvent();
113 /*! \brief Data transfer wrapper for GPU halo exchange
114 * \param [inout] d_ptr pointer to coordinates or force buffer in GPU memory
115 * \param [in] haloQuantity switch on whether X or F halo exchange is being performed
116 * \param [in] coordinatesReadyOnDeviceEvent event recorded when coordinates have been copied to device
118 void communicateHaloData(float3* d_ptr,
119 HaloQuantity haloQuantity,
120 GpuEventSynchronizer* coordinatesReadyOnDeviceEvent);
122 /*! \brief Data transfer for GPU halo exchange using CUDA memcopies
123 * \param [inout] sendPtr address to send data from
124 * \param [in] sendSize number of atoms to be sent
125 * \param [in] sendRank rank to send data to
126 * \param [inout] remotePtr remote address to recv data
127 * \param [in] recvRank rank to recv data from
129 void communicateHaloDataWithCudaDirect(void* sendPtr, int sendSize, int sendRank, void* remotePtr, int recvRank);
131 //! Domain decomposition object
132 gmx_domdec_t* dd_ = nullptr;
133 //! map of indices to be sent from this rank
134 gmx::HostVector<int> h_indexMap_;
135 //! device copy of index map
136 int* d_indexMap_ = nullptr;
137 //! number of elements in index map array
138 int indexMapSize_ = -1;
139 //! number of elements allocated in index map array
140 int indexMapSizeAlloc_ = -1;
141 //! device buffer for sending packed data
142 float3* d_sendBuf_ = nullptr;
143 //! number of atoms in sendbuf array
144 int sendBufSize_ = -1;
145 //! number of atoms allocated in sendbuf array
146 int sendBufSizeAlloc_ = -1;
147 //! device buffer for receiving packed data
148 float3* d_recvBuf_ = nullptr;
149 //! maximum size of packed buffer
150 int maxPackedBufferSize_ = 0;
151 //! number of atoms in recvbuf array
152 int recvBufSize_ = -1;
153 //! number of atoms allocated in recvbuf array
154 int recvBufSizeAlloc_ = -1;
155 //! rank to send data to for X
157 //! rank to recv data from for X
159 //! rank to send data to for F
161 //! rank to recv data from for F
163 //! send copy size from this rank for X
165 //! recv copy size to this rank for X
167 //! send copy size from this rank for F
169 //! recv copy size to this rank for F
171 //! number of home atoms - offset of local halo region
172 int numHomeAtoms_ = 0;
173 //! remote GPU coordinates buffer pointer for pushing data
174 void* remoteXPtr_ = nullptr;
175 //! remote GPU force buffer pointer for pushing data
176 void* remoteFPtr_ = nullptr;
177 //! Periodic Boundary Conditions for this rank
178 bool usePBC_ = false;
179 //! force shift buffer on device
180 float3* d_fShift_ = nullptr;
181 //! Event triggered when halo transfer has been launched with direct CUD memory copy
182 GpuEventSynchronizer* haloDataTransferLaunched_ = nullptr;
183 //! MPI communicator used for simulation
184 MPI_Comm mpi_comm_mysim_;
185 //! GPU context object
186 const DeviceContext& deviceContext_;
187 //! CUDA stream for local non-bonded calculations
188 cudaStream_t localStream_ = nullptr;
189 //! CUDA stream for non-local non-bonded calculations
190 cudaStream_t nonLocalStream_ = nullptr;
191 //! full coordinates buffer in GPU memory
192 float3* d_x_ = nullptr;
193 //! full forces buffer in GPU memory
194 float3* d_f_ = nullptr;
195 //! An event recorded once the exchanged forces are ready on the GPU
196 GpuEventSynchronizer fReadyOnDevice_;
197 //! The pulse corresponding to this halo exchange instance
199 //! Number of zones. Always 1 for 1-D case.
200 const int nzone_ = 1;