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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.h"
52 #include "gromacs/gpu_utils/hostallocator.h"
53 #include "gromacs/utility/gmxmpi.h"
60 /*! \brief switch for whether coordinates or force halo is being applied */
61 enum class HaloQuantity
67 /*! \internal \brief Class with interfaces and data for GPU Halo Exchange */
68 class GpuHaloExchange::Impl
72 /*! \brief Creates GPU Halo Exchange object.
74 * \param [inout] dd domdec structure
75 * \param [in] dimIndex the dimension index for this instance
76 * \param [in] mpi_comm_mysim communicator used for simulation
77 * \param [in] deviceContext GPU device context
78 * \param [in] pulse the communication pulse for this instance
79 * \param [in] wcycle The wallclock counter
81 Impl(gmx_domdec_t* dd,
83 MPI_Comm mpi_comm_mysim,
84 const DeviceContext& deviceContext,
86 gmx_wallcycle* wcycle);
90 * (Re-) Initialization for GPU halo exchange
91 * \param [in] d_coordinatesBuffer pointer to coordinates buffer in GPU memory
92 * \param [in] d_forcesBuffer pointer to forces buffer in GPU memory
94 void reinitHalo(float3* d_coordinatesBuffer, float3* d_forcesBuffer);
98 * GPU halo exchange of coordinates buffer
99 * \param [in] box Coordinate box (from which shifts will be constructed)
100 * \param [in] dependencyEvent Dependency event for this operation
101 * \returns Event recorded when this operation has been launched
103 GpuEventSynchronizer* communicateHaloCoordinates(const matrix box, GpuEventSynchronizer* dependencyEvent);
105 /*! \brief GPU halo exchange of force buffer
106 * \param [in] accumulateForces True if forces should accumulate, otherwise they are set
107 * \param [in] dependencyEvents Dependency events for this operation
109 void communicateHaloForces(bool accumulateForces,
110 FixedCapacityVector<GpuEventSynchronizer*, 2>* dependencyEvents);
112 /*! \brief Get the event synchronizer for the forces ready on device.
113 * \returns The event to synchronize the stream that consumes forces on device.
115 GpuEventSynchronizer* getForcesReadyOnDeviceEvent();
118 /*! \brief Data transfer wrapper for GPU halo exchange
119 * \param [in] sendPtr send buffer address
120 * \param [in] sendSize number of elements to send
121 * \param [in] sendRank rank of destination
122 * \param [in] recvPtr receive buffer address
123 * \param [in] recvSize number of elements to receive
124 * \param [in] recvRank rank of source
126 void communicateHaloData(float3* sendPtr, int sendSize, int sendRank, float3* recvPtr, int recvSize, int recvRank);
128 /*! \brief Data transfer for GPU halo exchange using CUDA memcopies
129 * \param [inout] sendPtr address to send data from
130 * \param [in] sendSize number of atoms to be sent
131 * \param [in] sendRank rank to send data to
132 * \param [in] remotePtr remote address to recv data
133 * \param [in] recvRank rank to recv data from
135 void communicateHaloDataWithCudaDirect(float3* sendPtr, int sendSize, int sendRank, float3* remotePtr, int recvRank);
137 /*! \brief Data transfer wrapper for GPU halo exchange using MPI_send and MPI_Recv
138 * \param [in] sendPtr send buffer address
139 * \param [in] sendSize number of elements to send
140 * \param [in] sendRank rank of destination
141 * \param [in] recvPtr receive buffer address
142 * \param [in] recvSize number of elements to receive
143 * \param [in] recvRank rank of source
145 void communicateHaloDataWithCudaMPI(float3* sendPtr,
152 /*! \brief Exchange coordinate-ready event with neighbor ranks and enqueue wait in halo stream
153 * \param [in] eventSync event recorded when coordinates/forces are ready to device
155 void enqueueWaitRemoteCoordinatesReadyEvent(GpuEventSynchronizer* coordinatesReadyOnDeviceEvent);
157 //! Domain decomposition object
158 gmx_domdec_t* dd_ = nullptr;
159 //! map of indices to be sent from this rank
160 gmx::HostVector<int> h_indexMap_;
161 //! device copy of index map
162 int* d_indexMap_ = nullptr;
163 //! number of elements in index map array
164 int indexMapSize_ = -1;
165 //! number of elements allocated in index map array
166 int indexMapSizeAlloc_ = -1;
167 //! device buffer for sending packed data
168 float3* d_sendBuf_ = nullptr;
169 //! number of atoms in sendbuf array
170 int sendBufSize_ = -1;
171 //! number of atoms allocated in sendbuf array
172 int sendBufSizeAlloc_ = -1;
173 //! device buffer for receiving packed data
174 float3* d_recvBuf_ = nullptr;
175 //! maximum size of packed buffer
176 int maxPackedBufferSize_ = 0;
177 //! number of atoms in recvbuf array
178 int recvBufSize_ = -1;
179 //! number of atoms allocated in recvbuf array
180 int recvBufSizeAlloc_ = -1;
181 //! rank to send data to for X
183 //! rank to recv data from for X
185 //! rank to send data to for F
187 //! rank to recv data from for F
189 //! send copy size from this rank for X
191 //! recv copy size to this rank for X
193 //! send copy size from this rank for F
195 //! recv copy size to this rank for F
197 //! number of home atoms - offset of local halo region
198 int numHomeAtoms_ = 0;
199 //! remote GPU coordinates buffer pointer for pushing data
200 float3* remoteXPtr_ = nullptr;
201 //! remote GPU force buffer pointer for pushing data
202 float3* remoteFPtr_ = nullptr;
203 //! Periodic Boundary Conditions for this rank
204 bool usePBC_ = false;
205 //! force shift buffer on device
206 float3* d_fShift_ = nullptr;
207 //! Event triggered when halo transfer has been launched with direct CUD memory copy
208 GpuEventSynchronizer* haloDataTransferLaunched_ = nullptr;
209 //! MPI communicator used for simulation
210 MPI_Comm mpi_comm_mysim_;
211 //! GPU context object
212 const DeviceContext& deviceContext_;
213 //! CUDA stream for this halo exchange
214 DeviceStream* haloStream_;
215 //! full coordinates buffer in GPU memory
216 float3* d_x_ = nullptr;
217 //! full forces buffer in GPU memory
218 float3* d_f_ = nullptr;
219 //! An event recorded once the exchanged forces are ready on the GPU
220 GpuEventSynchronizer fReadyOnDevice_;
221 //! The dimension index corresponding to this halo exchange instance
223 //! The pulse corresponding to this halo exchange instance
225 //! The wallclock counter
226 gmx_wallcycle* wcycle_ = nullptr;
227 //! The atom offset for receive (x) or send (f) for dimension index and pulse corresponding to this halo exchange instance
229 //! Event triggered when coordinate halo has been launched
230 GpuEventSynchronizer coordinateHaloLaunched_;