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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] localStream local NB CUDA stream
75 * \param [in] nonLocalStream non-local NB CUDA stream
76 * \param [in] pulse the communication pulse for this instance
78 Impl(gmx_domdec_t* dd, MPI_Comm mpi_comm_mysim, void* localStream, void* nonLocalStream, int pulse);
82 * (Re-) Initialization for GPU halo exchange
83 * \param [in] d_coordinatesBuffer pointer to coordinates buffer in GPU memory
84 * \param [in] d_forcesBuffer pointer to forces buffer in GPU memory
86 void reinitHalo(float3* d_coordinatesBuffer, float3* d_forcesBuffer);
90 * GPU halo exchange of coordinates buffer
91 * \param [in] box Coordinate box (from which shifts will be constructed)
92 * \param [in] coordinatesReadyOnDeviceEvent event recorded when coordinates have been copied to device
94 void communicateHaloCoordinates(const matrix box, GpuEventSynchronizer* coordinatesReadyOnDeviceEvent);
96 /*! \brief GPU halo exchange of force buffer
97 * \param[in] accumulateForces True if forces should accumulate, otherwise they are set
99 void communicateHaloForces(bool accumulateForces);
101 /*! \brief Get the event synchronizer for the forces ready on device.
102 * \returns The event to synchronize the stream that consumes forces on device.
104 GpuEventSynchronizer* getForcesReadyOnDeviceEvent();
107 /*! \brief Data transfer wrapper for GPU halo exchange
108 * \param [inout] d_ptr pointer to coordinates or force buffer in GPU memory
109 * \param [in] haloQuantity switch on whether X or F halo exchange is being performed
110 * \param [in] coordinatesReadyOnDeviceEvent event recorded when coordinates have been copied to device
112 void communicateHaloData(float3* d_ptr,
113 HaloQuantity haloQuantity,
114 GpuEventSynchronizer* coordinatesReadyOnDeviceEvent);
116 /*! \brief Data transfer for GPU halo exchange using CUDA memcopies
117 * \param [inout] sendPtr address to send data from
118 * \param [in] sendSize number of atoms to be sent
119 * \param [in] sendRank rank to send data to
120 * \param [inout] remotePtr remote address to recv data
121 * \param [in] recvRank rank to recv data from
123 void communicateHaloDataWithCudaDirect(void* sendPtr, int sendSize, int sendRank, void* remotePtr, int recvRank);
125 //! Domain decomposition object
126 gmx_domdec_t* dd_ = nullptr;
127 //! map of indices to be sent from this rank
128 gmx::HostVector<int> h_indexMap_;
129 //! device copy of index map
130 int* d_indexMap_ = nullptr;
131 //! number of elements in index map array
132 int indexMapSize_ = -1;
133 //! number of elements allocated in index map array
134 int indexMapSizeAlloc_ = -1;
135 //! device buffer for sending packed data
136 float3* d_sendBuf_ = nullptr;
137 //! number of atoms in sendbuf array
138 int sendBufSize_ = -1;
139 //! number of atoms allocated in sendbuf array
140 int sendBufSizeAlloc_ = -1;
141 //! device buffer for receiving packed data
142 float3* d_recvBuf_ = nullptr;
143 //! maximum size of packed buffer
144 int maxPackedBufferSize_ = 0;
145 //! number of atoms in recvbuf array
146 int recvBufSize_ = -1;
147 //! number of atoms allocated in recvbuf array
148 int recvBufSizeAlloc_ = -1;
149 //! rank to send data to for X
151 //! rank to recv data from for X
153 //! rank to send data to for F
155 //! rank to recv data from for F
157 //! send copy size from this rank for X
159 //! recv copy size to this rank for X
161 //! send copy size from this rank for F
163 //! recv copy size to this rank for F
165 //! number of home atoms - offset of local halo region
166 int numHomeAtoms_ = 0;
167 //! remote GPU coordinates buffer pointer for pushing data
168 void* remoteXPtr_ = nullptr;
169 //! remote GPU force buffer pointer for pushing data
170 void* remoteFPtr_ = nullptr;
171 //! Periodic Boundary Conditions for this rank
172 bool usePBC_ = false;
173 //! force shift buffer on device
174 float3* d_fShift_ = nullptr;
175 //! Event triggered when halo transfer has been launched with direct CUD memory copy
176 GpuEventSynchronizer* haloDataTransferLaunched_ = nullptr;
177 //! MPI communicator used for simulation
178 MPI_Comm mpi_comm_mysim_;
179 //! Dummy GPU context object
180 const DeviceContext deviceContext_;
181 //! CUDA stream for local non-bonded calculations
182 cudaStream_t localStream_ = nullptr;
183 //! CUDA stream for non-local non-bonded calculations
184 cudaStream_t nonLocalStream_ = nullptr;
185 //! full coordinates buffer in GPU memory
186 float3* d_x_ = nullptr;
187 //! full forces buffer in GPU memory
188 float3* d_f_ = nullptr;
189 //! An event recorded once the exchanged forces are ready on the GPU
190 GpuEventSynchronizer fReadyOnDevice_;
191 //! The pulse corresponding to this halo exchange instance
193 //! Number of zones. Always 1 for 1-D case.
194 const int nzone_ = 1;